#include <bits/stdc++.h>
using namespace std;

string s[110];
int n;
map<string, int> mp;
int main(){
  cin >> n;
  cin >> s[0];
  mp[s[0]]++;

  for(int i = 1;i < n;i++){
    cin >> s[i];
    if(s[i-1][s[i-1].size()-1] != s[i][0] || mp[s[i]] == 1){
      cout << "No" << endl;
      return 0;
    }
    mp[s[i]]++;
  }

  cout << "Yes" << endl;
  return 0;
}
