import java.util.*;
import static java.lang.System.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(in);
        int N;
        N = scanner.nextInt();
        HashMap<String, Boolean> seen = new HashMap<>();
        String[] words = new String[N+1];
        for(int i = 0; i < N; ++i) {
            words[i] = scanner.next();
        }
        String ans = "Yes";
        for(int i = 1; i < N; ++i) {
            seen.put(words[i-1], true);
            if(words[i].charAt(0) != words[i-1].charAt(words[i-1].length()-1))
                ans = "No";
            if(seen.containsKey(words[i]))
                ans = "No";
        }
        System.out.println(ans);
    }
}
/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