#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    string s[100];
    set<string> q;
    for(int i = 0;i < n;i++){
        cin >> s[i];
        if(q.count(s[i]) != 0 || (i != 0 && s[i-1][s[i-1].size()-1] != s[i][0])){
            cout << "No" << endl;
            return 0;
        }
        q.insert(s[i]);
    }
    cout << "Yes" << endl;
}