import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author GYSHGX868
 */
public class Main {
  public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    TaskC solver = new TaskC();
    solver.solve(1, in, out);
    out.close();
  }

  static class TaskC {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      char[] s = in.nextString().toCharArray();
      for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      }
      out.printLine("YES");
    }

    private int judge(char[] s, int from, char[] substring) {
      for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      }
      return from + substring.length - 1;
    }

  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public String nextString() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      boolean isSpaceChar(int ch);

    }

  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }

  }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.OutputStream; OutputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.io.BufferedWriter; BufferedWriter java.io import java.io.Writer; Writer java.io import java.io.OutputStreamWriter; OutputStreamWriter java.io import java.util.InputMismatchException; InputMismatchException java.util import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io public class Main {
  public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    TaskC solver = new TaskC();
    solver.solve(1, in, out);
    out.close();
  }

  static class TaskC {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      char[] s = in.nextString().toCharArray();
      for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      }
      out.printLine("YES");
    }

    private int judge(char[] s, int from, char[] substring) {
      for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      }
      return from + substring.length - 1;
    }

  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public String nextString() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      boolean isSpaceChar(int ch);

    }

  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }

  }
} Main public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    TaskC solver = new TaskC();
    solver.solve(1, in, out);
    out.close();
  } main {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    TaskC solver = new TaskC();
    solver.solve(1, in, out);
    out.close();
  } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) OutputWriter out = new OutputWriter(outputStream); out new OutputWriter(outputStream) TaskC solver = new TaskC(); solver new TaskC() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class TaskC {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      char[] s = in.nextString().toCharArray();
      for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      }
      out.printLine("YES");
    }

    private int judge(char[] s, int from, char[] substring) {
      for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      }
      return from + substring.length - 1;
    }

  } TaskC public void solve(int testNumber, InputReader in, OutputWriter out) {
      char[] s = in.nextString().toCharArray();
      for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      }
      out.printLine("YES");
    } solve {
      char[] s = in.nextString().toCharArray();
      for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      }
      out.printLine("YES");
    } char[] s = in.nextString().toCharArray(); s in.nextString().toCharArray() in.nextString().toCharArray in.nextString() in.nextString in for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      } int i = 0; int i = 0; i 0 i < s.length i s.length s s.length i++ i++ i {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      } {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      } if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        } s[i] == 'e' s[i] s i 'e' {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'}); e1 judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'}) judge s i new char[]{'e', 'r', 'a', 's', 'e', 'r'} if (e1 != -1) {
            i = e1;
            continue;
          } e1 != -1 e1 -1 1 {
            i = e1;
            continue;
          } i = e1 i e1 continue; int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'}); e2 judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'}) judge s i new char[]{'e', 'r', 'a', 's', 'e'} if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          } e2 != -1 e2 -1 1 {
            i = e2;
          } i = e2 i e2 {
            out.printLine("NO");
            return;
          } out.printLine("NO") out.printLine out "NO" return; if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        } s[i] == 'd' s[i] s i 'd' {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'}); e1 judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'}) judge s i new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'} if (e1 != -1) {
            i = e1;
            continue;
          } e1 != -1 e1 -1 1 {
            i = e1;
            continue;
          } i = e1 i e1 continue; int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'}); e2 judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'}) judge s i new char[]{'d', 'r', 'e', 'a', 'm'} if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          } e2 != -1 e2 -1 1 {
            i = e2;
          } i = e2 i e2 {
            out.printLine("NO");
            return;
          } out.printLine("NO") out.printLine out "NO" return; if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        } s[i] == 'a' s[i] s i 'a' {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          } i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r' s[i - 2] == 'e' i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r' i - 3 >= 0 i - 3 i 3 0 s[i - 3] == 'm' s[i - 3] s i - 3 i 3 'm' s[i - 2] == 'e' s[i - 2] s i - 2 i 2 'e' s[i - 1] == 'r' s[i - 1] s i - 1 i 1 'r' {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'}); e1 judge(s, i, new char[]{'a', 's', 'e', 'r'}) judge s i new char[]{'a', 's', 'e', 'r'} if (e1 != -1) {
              i = e1;
              continue;
            } e1 != -1 e1 -1 1 {
              i = e1;
              continue;
            } i = e1 i e1 continue; int e2 = judge(s, i, new char[]{'a', 's', 'e'}); e2 judge(s, i, new char[]{'a', 's', 'e'}) judge s i new char[]{'a', 's', 'e'} if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            } e2 != -1 e2 -1 1 {
              i = e2;
            } i = e2 i e2 {
              out.printLine("NO");
              return;
            } out.printLine("NO") out.printLine out "NO" return; {
            out.printLine("NO");
            return;
          } out.printLine("NO") out.printLine out "NO" return; {
          out.printLine("NO");
          return;
        } out.printLine("NO") out.printLine out "NO" return; out.printLine("YES") out.printLine out "YES" int testNumber testNumber InputReader in in OutputWriter out out private int judge(char[] s, int from, char[] substring) {
      for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      }
      return from + substring.length - 1;
    } judge {
      for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      }
      return from + substring.length - 1;
    } for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      } int i = 1; int i = 1; i 1 i < substring.length i substring.length substring substring.length i++ i++ i {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      } {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      } if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        } from + i >= s.length || s[from + i] != substring[i] from + i >= s.length from + i from i s.length s s.length s[from + i] != substring[i] s[from + i] s from + i from i substring[i] substring i {
          return -1;
        } return -1; -1 1 return from + substring.length - 1; from + substring.length - 1 from + substring.length from substring.length substring substring.length 1 char[] s s int from from char[] substring substring static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public String nextString() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      boolean isSpaceChar(int ch);

    }

  } InputReader private InputStream stream; stream private byte[] buf = new byte[1024]; buf new byte[1024] 1024 private int curChar; curChar private int numChars; numChars private InputReader.SpaceCharFilter filter; filter public InputReader(InputStream stream) {
      this.stream = stream;
    } InputReader {
      this.stream = stream;
    } this.stream = stream this.stream this this.stream stream InputStream stream stream public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    } read {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    } if (numChars == -1) {
        throw new InputMismatchException();
      } numChars == -1 numChars -1 1 {
        throw new InputMismatchException();
      } throw new InputMismatchException(); new InputMismatchException() if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      } curChar >= numChars curChar numChars {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      } curChar = 0 curChar 0 try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        } catch (IOException e) {
          throw new InputMismatchException();
        } IOException e {
          throw new InputMismatchException();
        } throw new InputMismatchException(); new InputMismatchException() {
          numChars = stream.read(buf);
        } numChars = stream.read(buf) numChars stream.read(buf) stream.read stream buf if (numChars <= 0) {
          return -1;
        } numChars <= 0 numChars 0 {
          return -1;
        } return -1; -1 1 return buf[curChar++]; buf[curChar++] buf curChar++ curChar public String nextString() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    } nextString {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    } int c = read(); c read() read while (isSpaceChar(c)) {
        c = read();
      } isSpaceChar(c) isSpaceChar c {
        c = read();
      } c = read() c read() read StringBuilder res = new StringBuilder(); res new StringBuilder() do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c)); !isSpaceChar(c) isSpaceChar(c) isSpaceChar c {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        } Character.isValidCodePoint(c) Character.isValidCodePoint Character c {
          res.appendCodePoint(c);
        } res.appendCodePoint(c) res.appendCodePoint res c c = read() c read() read return res.toString(); res.toString() res.toString res public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    } isSpaceChar {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    } if (filter != null) {
        return filter.isSpaceChar(c);
      } filter != null filter null {
        return filter.isSpaceChar(c);
      } return filter.isSpaceChar(c); filter.isSpaceChar(c) filter.isSpaceChar filter c return isWhitespace(c); isWhitespace(c) isWhitespace c int c c public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    } isWhitespace {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    } return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1; c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 c == '\t' c == '\r' c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 c == ' ' c ' ' c == '\n' c '\n' c == '\r' c '\r' c == '\t' c '\t' c == -1 c -1 1 int c c public interface SpaceCharFilter {
      boolean isSpaceChar(int ch);

    } SpaceCharFilter boolean isSpaceChar(int ch); isSpaceChar int ch ch static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }

  } OutputWriter private final PrintWriter writer; writer public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    } OutputWriter {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    } writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream))) writer new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream))) OutputStream outputStream outputStream public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    } OutputWriter {
      this.writer = new PrintWriter(writer);
    } this.writer = new PrintWriter(writer) this.writer this this.writer new PrintWriter(writer) Writer writer writer public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    } print {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    } for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      } int i = 0; int i = 0; i 0 i < objects.length i objects.length objects objects.length i++ i++ i {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      } {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      } if (i != 0) {
          writer.print(' ');
        } i != 0 i 0 {
          writer.print(' ');
        } writer.print(' ') writer.print writer ' ' writer.print(objects[i]) writer.print writer objects[i] objects i Object... objects objects public void printLine(Object... objects) {
      print(objects);
      writer.println();
    } printLine {
      print(objects);
      writer.println();
    } print(objects) print objects writer.println() writer.println writer Object... objects objects public void close() {
      writer.close();
    } close {
      writer.close();
    } writer.close() writer.close writer public class Main {
  public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    TaskC solver = new TaskC();
    solver.solve(1, in, out);
    out.close();
  }

  static class TaskC {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      char[] s = in.nextString().toCharArray();
      for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      }
      out.printLine("YES");
    }

    private int judge(char[] s, int from, char[] substring) {
      for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      }
      return from + substring.length - 1;
    }

  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public String nextString() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      boolean isSpaceChar(int ch);

    }

  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }

  }
} public class Main {
  public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    TaskC solver = new TaskC();
    solver.solve(1, in, out);
    out.close();
  }

  static class TaskC {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      char[] s = in.nextString().toCharArray();
      for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      }
      out.printLine("YES");
    }

    private int judge(char[] s, int from, char[] substring) {
      for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      }
      return from + substring.length - 1;
    }

  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public String nextString() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      boolean isSpaceChar(int ch);

    }

  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }

  }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author GYSHGX868
 */
public class Main {
  public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    TaskC solver = new TaskC();
    solver.solve(1, in, out);
    out.close();
  }

  static class TaskC {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      char[] s = in.nextString().toCharArray();
      for (int i = 0; i < s.length; i++) {
        if (s[i] == 'e') {
          int e1 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'e', 'r', 'a', 's', 'e'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'd') {
          int e1 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm', 'e', 'r'});
          if (e1 != -1) {
            i = e1;
            continue;
          }
          int e2 = judge(s, i, new char[]{'d', 'r', 'e', 'a', 'm'});
          if (e2 != -1) {
            i = e2;
          } else {
            out.printLine("NO");
            return;
          }
        } else if (s[i] == 'a') {
          if (i - 3 >= 0 && s[i - 3] == 'm' && s[i - 2] == 'e' && s[i - 1] == 'r') {
            int e1 = judge(s, i, new char[]{'a', 's', 'e', 'r'});
            if (e1 != -1) {
              i = e1;
              continue;
            }
            int e2 = judge(s, i, new char[]{'a', 's', 'e'});
            if (e2 != -1) {
              i = e2;
            } else {
              out.printLine("NO");
              return;
            }
          } else {
            out.printLine("NO");
            return;
          }
        } else {
          out.printLine("NO");
          return;
        }
      }
      out.printLine("YES");
    }

    private int judge(char[] s, int from, char[] substring) {
      for (int i = 1; i < substring.length; i++) {
        if (from + i >= s.length || s[from + i] != substring[i]) {
          return -1;
        }
      }
      return from + substring.length - 1;
    }

  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public String nextString() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      boolean isSpaceChar(int ch);

    }

  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }

  }
}

