import java.util.*;
class Main
{
  public static void main(String[] args) {
    
    Scanner scan =new Scanner(System.in);
    int n = scan.nextInt();
   	String[] str = new String[n];
       int count = 0 ;
    ArrayList<String> st = new ArrayList<String>();
      for(int i = 0 ; i<n ; i++){
      str[i] = scan.next();
        if(st.contains(str[i])){
        count++;
        break;
      }else{
        st.add(str[i]);
      }
    }
    
 	if(count==0){
      for(int i = 0 ; i<n-1 ; i++){

        if(str[i].charAt(str[i].length()-1) != str[i+1].charAt(0)){
          count++;
          break;
        } 
      }
    }
    if(count!=0){
      System.out.println("No");
    }else{
      
      System.out.println("Yes");
    }
  }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz