import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    int N = scanner.nextInt();
    HashSet<String> words = new HashSet<>();
    String lastWord = scanner.next();
    words.add(lastWord);
    for (int i = 1; i < N; ++i) {
      String word = scanner.next();
      if (word.charAt(0) != lastWord.charAt(lastWord.length() - 1)) {
        System.out.println("No");
        return;
      }
      if (words.contains(word)) {
        System.out.println("No");
        return;
      }
      lastWord = word;
      words.add(word);
    }
    System.out.println("Yes");
    return;
  }
}
/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