import java.io.*;
import java.util.*;
import java.util.stream.IntStream;

public class Main {
  private static PrintWriter out;

  public static void main(String[] args) {
    Main main = new Main();
    try {
      main.run(args);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  private void run(String[] arguments) throws Exception {
    MyScanner sc = new MyScanner();
    out = new PrintWriter(new BufferedOutputStream(System.out));

    ArrayList<String> arrayWordList = new ArrayList<>();
    int n = sc.nextInt();
    String ans = "Yes";

    for (int i = 0; i < n; i++) {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    }
    out.println(ans);
    out.close();
  }

  /*
   * Form: http://codeforces.com/blog/entry/7018
   */
  private class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    MyScanner() {
      br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }

    int nextInt() {
      return Integer.parseInt(next());
    }

    long nextLong() {
      return Long.parseLong(next());
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    String nextLine() {
      String str = "";
      try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    }
  }
} import java.io.*; io.* java import java.util.*; util.* java import java.util.stream.IntStream; IntStream java.util.stream public class Main {
  private static PrintWriter out;

  public static void main(String[] args) {
    Main main = new Main();
    try {
      main.run(args);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  private void run(String[] arguments) throws Exception {
    MyScanner sc = new MyScanner();
    out = new PrintWriter(new BufferedOutputStream(System.out));

    ArrayList<String> arrayWordList = new ArrayList<>();
    int n = sc.nextInt();
    String ans = "Yes";

    for (int i = 0; i < n; i++) {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    }
    out.println(ans);
    out.close();
  }

  /*
   * Form: http://codeforces.com/blog/entry/7018
   */
  private class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    MyScanner() {
      br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }

    int nextInt() {
      return Integer.parseInt(next());
    }

    long nextLong() {
      return Long.parseLong(next());
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    String nextLine() {
      String str = "";
      try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    }
  }
} Main private static PrintWriter out; out public static void main(String[] args) {
    Main main = new Main();
    try {
      main.run(args);
    } catch (Exception e) {
      e.printStackTrace();
    }
  } main {
    Main main = new Main();
    try {
      main.run(args);
    } catch (Exception e) {
      e.printStackTrace();
    }
  } Main main = new Main(); main new Main() try {
      main.run(args);
    } catch (Exception e) {
      e.printStackTrace();
    } catch (Exception e) {
      e.printStackTrace();
    } Exception e {
      e.printStackTrace();
    } e.printStackTrace() e.printStackTrace e {
      main.run(args);
    } main.run(args) main.run main args String[] args args private void run(String[] arguments) throws Exception {
    MyScanner sc = new MyScanner();
    out = new PrintWriter(new BufferedOutputStream(System.out));

    ArrayList<String> arrayWordList = new ArrayList<>();
    int n = sc.nextInt();
    String ans = "Yes";

    for (int i = 0; i < n; i++) {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    }
    out.println(ans);
    out.close();
  } run {
    MyScanner sc = new MyScanner();
    out = new PrintWriter(new BufferedOutputStream(System.out));

    ArrayList<String> arrayWordList = new ArrayList<>();
    int n = sc.nextInt();
    String ans = "Yes";

    for (int i = 0; i < n; i++) {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    }
    out.println(ans);
    out.close();
  } MyScanner sc = new MyScanner(); sc new MyScanner() out = new PrintWriter(new BufferedOutputStream(System.out)) out new PrintWriter(new BufferedOutputStream(System.out)) ArrayList<String> arrayWordList = new ArrayList<>(); arrayWordList new ArrayList<>() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc String ans = "Yes"; ans "Yes" for (int i = 0; i < n; i++) {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    } {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    } String word = sc.next(); word sc.next() sc.next sc if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      } arrayWordList.contains(word) arrayWordList.contains arrayWordList word {
        ans = "No";
        break;
      } ans = "No" ans "No" break; if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      } i > 0 i 0 {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      } String beforeWord = arrayWordList.get(i - 1); beforeWord arrayWordList.get(i - 1) arrayWordList.get arrayWordList i - 1 i 1 char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1]; beforeLastChar beforeWord.toCharArray()[beforeWord.length() - 1] beforeWord.toCharArray() beforeWord.toCharArray beforeWord beforeWord.length() - 1 beforeWord.length() beforeWord.length beforeWord 1 char thisFirstChar = word.toCharArray()[0]; thisFirstChar word.toCharArray()[0] word.toCharArray() word.toCharArray word 0 if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        } beforeLastChar != thisFirstChar beforeLastChar thisFirstChar {
          ans = "No";
          break;
        } ans = "No" ans "No" break; arrayWordList.add(word) arrayWordList.add arrayWordList word out.println(ans) out.println out ans out.close() out.close out String[] arguments arguments private class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    MyScanner() {
      br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }

    int nextInt() {
      return Integer.parseInt(next());
    }

    long nextLong() {
      return Long.parseLong(next());
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    String nextLine() {
      String str = "";
      try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    }
  } MyScanner BufferedReader br; br StringTokenizer st; st MyScanner() {
      br = new BufferedReader(new InputStreamReader(System.in));
    } MyScanner {
      br = new BufferedReader(new InputStreamReader(System.in));
    } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    } next {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    } while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      } try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        } catch (IOException e) {
          e.printStackTrace();
        } IOException e {
          e.printStackTrace();
        } e.printStackTrace() e.printStackTrace e {
          st = new StringTokenizer(br.readLine());
        } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
      return Integer.parseInt(next());
    } nextInt {
      return Integer.parseInt(next());
    } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
      return Long.parseLong(next());
    } nextLong {
      return Long.parseLong(next());
    } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() {
      return Double.parseDouble(next());
    } nextDouble {
      return Double.parseDouble(next());
    } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() {
      String str = "";
      try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    } nextLine {
      String str = "";
      try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    } String str = ""; str "" try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      } catch (IOException e) {
        e.printStackTrace();
      } IOException e {
        e.printStackTrace();
      } e.printStackTrace() e.printStackTrace e {
        str = br.readLine();
      } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
  private static PrintWriter out;

  public static void main(String[] args) {
    Main main = new Main();
    try {
      main.run(args);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  private void run(String[] arguments) throws Exception {
    MyScanner sc = new MyScanner();
    out = new PrintWriter(new BufferedOutputStream(System.out));

    ArrayList<String> arrayWordList = new ArrayList<>();
    int n = sc.nextInt();
    String ans = "Yes";

    for (int i = 0; i < n; i++) {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    }
    out.println(ans);
    out.close();
  }

  /*
   * Form: http://codeforces.com/blog/entry/7018
   */
  private class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    MyScanner() {
      br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }

    int nextInt() {
      return Integer.parseInt(next());
    }

    long nextLong() {
      return Long.parseLong(next());
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    String nextLine() {
      String str = "";
      try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    }
  }
} public class Main {
  private static PrintWriter out;

  public static void main(String[] args) {
    Main main = new Main();
    try {
      main.run(args);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  private void run(String[] arguments) throws Exception {
    MyScanner sc = new MyScanner();
    out = new PrintWriter(new BufferedOutputStream(System.out));

    ArrayList<String> arrayWordList = new ArrayList<>();
    int n = sc.nextInt();
    String ans = "Yes";

    for (int i = 0; i < n; i++) {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    }
    out.println(ans);
    out.close();
  }

  /*
   * Form: http://codeforces.com/blog/entry/7018
   */
  private class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    MyScanner() {
      br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }

    int nextInt() {
      return Integer.parseInt(next());
    }

    long nextLong() {
      return Long.parseLong(next());
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    String nextLine() {
      String str = "";
      try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    }
  }
} Main
import java.io.*;
import java.util.*;
import java.util.stream.IntStream;

public class Main {
  private static PrintWriter out;

  public static void main(String[] args) {
    Main main = new Main();
    try {
      main.run(args);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  private void run(String[] arguments) throws Exception {
    MyScanner sc = new MyScanner();
    out = new PrintWriter(new BufferedOutputStream(System.out));

    ArrayList<String> arrayWordList = new ArrayList<>();
    int n = sc.nextInt();
    String ans = "Yes";

    for (int i = 0; i < n; i++) {
      String word = sc.next();
      if (arrayWordList.contains(word)) {
        ans = "No";
        break;
      }
      if (i > 0) {
        String beforeWord = arrayWordList.get(i - 1);
        char beforeLastChar = beforeWord.toCharArray()[beforeWord.length() - 1];
        char thisFirstChar = word.toCharArray()[0];
        if (beforeLastChar != thisFirstChar) {
          ans = "No";
          break;
        }
      }
      arrayWordList.add(word);
    }
    out.println(ans);
    out.close();
  }

  /*
   * Form: http://codeforces.com/blog/entry/7018
   */
  private class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    MyScanner() {
      br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }

    int nextInt() {
      return Integer.parseInt(next());
    }

    long nextLong() {
      return Long.parseLong(next());
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    String nextLine() {
      String str = "";
      try {
        str = br.readLine();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return str;
    }
  }
}
