import java.util.Scanner;

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

    int N = Integer.parseInt(sc.nextLine());
    String[] W = new String[N];
    for (int i=0; i<N; i++) {
      W[i] = sc.nextLine();
    }


    for (int i=1; i<N; i++) {
      for (int j=0; j<i; j++) {
        if (W[i].equals(W[j])) {
          System.out.println("No");
          return;
        }
      }

      char lastChar = W[i-1].charAt(W[i-1].length()-1);
      if (!W[i].startsWith(String.valueOf(lastChar))) {
        System.out.println("No");
        return;
      }
    }

    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