import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int flag = 0;
		String[] W = new String[N];
		for(int i = 0; i < N; i++) {
			W[i] = sc.next();
		}

		for(int i = 0; i < N-1; i++) {
			if(W[i].charAt(W[i].length() -1) != W[i+1].charAt(0)) {
				flag = 1;
				System.out.println("No");
				break;
			}
		}

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

		if(flag == 0) {
			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