import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        @SuppressWarnings("resource")
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String[] s = new String[n];
        for (int i = 0 ; i < n ; i++) {
            s[i] = sc.next();
        }
        boolean flg = true;
        for (int i = 0 ; i < n ; i++) {
            for (int j = i + 1 ; j < n ; j++) {
                if (s[i].equals(s[j])) flg = false;
            }
        }
        for (int i = 0 ; i < n - 1 ; i++) {
            if (s[i].charAt(s[i].length() - 1) != s[i + 1].charAt(0)) flg = false;
        }
        System.out.println(flg ? "Yes" : "No");
    }

}
/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