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

int main() {
  set<string> d;
  int n;
  cin >> n;
  
  char last;
  string s;
  for(int i=0; i<n; i++) {
  	cin >> s;
    if(i > 0) {
      if(d.count(s) || s[0] != last) {
        cout << "No" << endl;
        return 0;
      }
    }
    d.insert(s);
    last = *(s.end()-1);
  }
  cout << "Yes" << endl;
  return 0;
}