import java.util.*;
 
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        boolean boo = true;
        String words[] = new String[n];
        words[0] = sc.next();
        String str[] = words[0].split("");
        String endC = str[str.length -1];
        for(int i=1; i<n; i++){
            String s = sc.next();
            if(Arrays.asList(words).contains(s)) boo = false;
            String nowStr[] = s.split("");
            String startC = nowStr[0];
            if(!startC.equals(endC)) boo = false;
            endC = nowStr[nowStr.length -1];
            words[i] = s;
        }
        if(boo) System.out.println("Yes");
        else System.out.println("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