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