import java.util.ArrayList;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<String> list = new ArrayList<>();
		String newWord;

		for (int i = 0; i < N; i++) {
			newWord = sc.next();
			if (list.contains(newWord)
					|| (!list.isEmpty() && !(list.get(list.size() - 1)).endsWith(String.valueOf(newWord.charAt(0))))) {
				System.out.println("No");
				return;
			} else {
				list.add(newWord);
			}
		}
		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