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

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

  
} public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    String W[] = new String[N];
    for(int i=0;i<N;i++){
      W[i]=sc.next();
    }
    for(int i=0;i<N-1;i++){
      if(!W[i].substring(W[i].length()-1,W[i].length()).equals(W[i+1].substring(0,1))){
        System.out.println("No");
        return;
      }
    }
    Arrays.sort(W);
    for(int i=0;i<N-1;i++){
      if(W[i].equals(W[i+1])){
        System.out.println("No");
        return;
      }
    }
    System.out.println("Yes");
         
  }
  

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

  
}