#include <bits/stdc++.h>
 
using namespace std;
 
int main()
{
  int n;
  string s;
  char c;
  map<string, bool> m;
  string ans = "Yes";
  cin >> n >> s;
  m[s] = 1;
  c = s.back();
  n--;
  while(n--) {
    cin >> s;
    if(s[0] != c || m[s]) {
     ans = "No";
    }
 	m[s] = 1;
    c = s.back();
  }
  cout << ans << endl;
}
