#include<bits/stdc++.h>
#include<math.h>
using namespace std;
typedef long long ll;
const int INF = 1<<30;

int main(){
  int n;cin>>n;bool ans=true;
  char pre;map<string, int> count;
  for(int i=0;i<n;i++){
    string s;cin>>s;
    if((i!=0&&pre!=s[0])||count[s]++>0){ans=false;}
    pre=s[s.size()-1];
  }
  cout << (ans?"Yes":"No") << endl;
}
