import java.util.*;

class Main {
  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    String s[] = new String[n];
    for (int i = 0; i < n; i++) {
      s[i] = sc.next();
      if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      }
    }
    System.out.println("Yes");
  }
} import java.util.*; util.* java class Main {
  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    String s[] = new String[n];
    for (int i = 0; i < n; i++) {
      s[i] = sc.next();
      if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      }
    }
    System.out.println("Yes");
  }
} Main public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    String s[] = new String[n];
    for (int i = 0; i < n; i++) {
      s[i] = sc.next();
      if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      }
    }
    System.out.println("Yes");
  } main {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    String s[] = new String[n];
    for (int i = 0; i < n; i++) {
      s[i] = sc.next();
      if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      }
    }
    System.out.println("Yes");
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc String s[] = new String[n]; s new String[n] n for (int i = 0; i < n; i++) {
      s[i] = sc.next();
      if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      }
    } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
      s[i] = sc.next();
      if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      }
    } {
      s[i] = sc.next();
      if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      }
    } s[i] = sc.next() s[i] s i sc.next() sc.next sc if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      } i > 0 i 0 {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      } if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        } s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0) s[i-1].charAt(s[i-1].length()-1) s[i-1].charAt s[i-1] s i-1 i 1 s[i-1].length()-1 s[i-1].length() s[i-1].length s[i-1] s i-1 i 1 1 s[i].charAt(0) s[i].charAt s[i] s i 0 {
          System.out.println("No");
          return;
        } System.out.println("No") System.out.println System.out System System.out "No" return; for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        } int j = 0; int j = 0; j 0 j < i j i j++ j++ j {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        } {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        } if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          } s[j].equals(s[i]) s[j].equals s[j] s j s[i] s i {
            System.out.println("No");
            return;
          } System.out.println("No") System.out.println System.out System System.out "No" return; System.out.println("Yes") System.out.println System.out System System.out "Yes" String args[] args
import java.util.*;

class Main {
  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    String s[] = new String[n];
    for (int i = 0; i < n; i++) {
      s[i] = sc.next();
      if (i > 0) {
        if (s[i-1].charAt(s[i-1].length()-1) != s[i].charAt(0)) {
          System.out.println("No");
          return;
        }
        for (int j = 0; j < i; j++) {
          if (s[j].equals(s[i])) {
            System.out.println("No");
            return;
          }
        }
      }
    }
    System.out.println("Yes");
  }
}
