#include <bits/stdc++.h>

using namespace std;


#define MAXN 101
int main() {
  int n;
  string w[MAXN];
  set<string> s;
  cin >> n;
  bool ans = true;
  for (int i = 0; i < n; ++i) {
    cin >> w[i];
    ans &= !s.count(w[i]) && (!i || *w[i-1].rbegin()==w[i][0]);
    s.insert(w[i]);

  }
  cout << (ans ? "Yes" : "No") << endl;
  return 0;
}
