import java.util.*;
public class Main {

  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      int n = sc.nextInt();
      Set<String> said = new HashSet<>();
      
      char prevChar = '0';
      for(int i = 0; i < n; i++) {
        String word = sc.next();
        if(said.contains(word) || i > 0 && prevChar != word.charAt(0)) {
          System.out.println("No");
          return;
        }
        said.add(word);
        prevChar = word.charAt(word.length() - 1);
      }
      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