import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ABC049C solver = new ABC049C();
        solver.solve(1, in, out);
        out.close();
    }

    static class ABC049C {
        static String[] strs = {
                "dream",
                "dreamer",
                "erase",
                "eraser"
        };

        public void solve(int testNumber, Scanner in, PrintWriter out) {
            String s = in.next();

            s = s.replaceAll(strs[3], "-");
            s = s.replaceAll(strs[2], "-");
            s = s.replaceAll(strs[1], "-");
            s = s.replaceAll(strs[0], "-");
            s = s.replaceAll("-", "");

            if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            }

        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ABC049C solver = new ABC049C();
        solver.solve(1, in, out);
        out.close();
    }

    static class ABC049C {
        static String[] strs = {
                "dream",
                "dreamer",
                "erase",
                "eraser"
        };

        public void solve(int testNumber, Scanner in, PrintWriter out) {
            String s = in.next();

            s = s.replaceAll(strs[3], "-");
            s = s.replaceAll(strs[2], "-");
            s = s.replaceAll(strs[1], "-");
            s = s.replaceAll(strs[0], "-");
            s = s.replaceAll("-", "");

            if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            }

        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ABC049C solver = new ABC049C();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ABC049C solver = new ABC049C();
        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 Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) ABC049C solver = new ABC049C(); solver new ABC049C() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class ABC049C {
        static String[] strs = {
                "dream",
                "dreamer",
                "erase",
                "eraser"
        };

        public void solve(int testNumber, Scanner in, PrintWriter out) {
            String s = in.next();

            s = s.replaceAll(strs[3], "-");
            s = s.replaceAll(strs[2], "-");
            s = s.replaceAll(strs[1], "-");
            s = s.replaceAll(strs[0], "-");
            s = s.replaceAll("-", "");

            if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            }

        }

    } ABC049C static String[] strs = {
                "dream",
                "dreamer",
                "erase",
                "eraser"
        }; strs {
                "dream",
                "dreamer",
                "erase",
                "eraser"
        } "dream" "dreamer" "erase" "eraser" public void solve(int testNumber, Scanner in, PrintWriter out) {
            String s = in.next();

            s = s.replaceAll(strs[3], "-");
            s = s.replaceAll(strs[2], "-");
            s = s.replaceAll(strs[1], "-");
            s = s.replaceAll(strs[0], "-");
            s = s.replaceAll("-", "");

            if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            }

        } solve {
            String s = in.next();

            s = s.replaceAll(strs[3], "-");
            s = s.replaceAll(strs[2], "-");
            s = s.replaceAll(strs[1], "-");
            s = s.replaceAll(strs[0], "-");
            s = s.replaceAll("-", "");

            if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            }

        } String s = in.next(); s in.next() in.next in s = s.replaceAll(strs[3], "-") s s.replaceAll(strs[3], "-") s.replaceAll s strs[3] strs 3 "-" s = s.replaceAll(strs[2], "-") s s.replaceAll(strs[2], "-") s.replaceAll s strs[2] strs 2 "-" s = s.replaceAll(strs[1], "-") s s.replaceAll(strs[1], "-") s.replaceAll s strs[1] strs 1 "-" s = s.replaceAll(strs[0], "-") s s.replaceAll(strs[0], "-") s.replaceAll s strs[0] strs 0 "-" s = s.replaceAll("-", "") s s.replaceAll("-", "") s.replaceAll s "-" "" if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            } s.length() == 0 s.length() s.length s 0 {
                out.println("YES");
            } out.println("YES") out.println out "YES" {
                out.println("NO");
            } out.println("NO") out.println out "NO" int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ABC049C solver = new ABC049C();
        solver.solve(1, in, out);
        out.close();
    }

    static class ABC049C {
        static String[] strs = {
                "dream",
                "dreamer",
                "erase",
                "eraser"
        };

        public void solve(int testNumber, Scanner in, PrintWriter out) {
            String s = in.next();

            s = s.replaceAll(strs[3], "-");
            s = s.replaceAll(strs[2], "-");
            s = s.replaceAll(strs[1], "-");
            s = s.replaceAll(strs[0], "-");
            s = s.replaceAll("-", "");

            if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            }

        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ABC049C solver = new ABC049C();
        solver.solve(1, in, out);
        out.close();
    }

    static class ABC049C {
        static String[] strs = {
                "dream",
                "dreamer",
                "erase",
                "eraser"
        };

        public void solve(int testNumber, Scanner in, PrintWriter out) {
            String s = in.next();

            s = s.replaceAll(strs[3], "-");
            s = s.replaceAll(strs[2], "-");
            s = s.replaceAll(strs[1], "-");
            s = s.replaceAll(strs[0], "-");
            s = s.replaceAll("-", "");

            if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            }

        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ABC049C solver = new ABC049C();
        solver.solve(1, in, out);
        out.close();
    }

    static class ABC049C {
        static String[] strs = {
                "dream",
                "dreamer",
                "erase",
                "eraser"
        };

        public void solve(int testNumber, Scanner in, PrintWriter out) {
            String s = in.next();

            s = s.replaceAll(strs[3], "-");
            s = s.replaceAll(strs[2], "-");
            s = s.replaceAll(strs[1], "-");
            s = s.replaceAll(strs[0], "-");
            s = s.replaceAll("-", "");

            if (s.length() == 0) {
                out.println("YES");
            } else {
                out.println("NO");
            }

        }

    }
}

