#include<bits/stdc++.h>
using namespace std;
int n,i,j,a,b,c,d;
string w[100];
int main()
{
  for(cin>>n>>w[0],i=1;i<n;i++){
    cin>>w[i];
    if(w[i-1][w[i-1].size()-1]!=w[i][0])return cout<<"No",0;
    for(j=0;j<i;j++)if(w[j].compare(w[i])==0)return cout<<"No",0;
  }
  cout<<"Yes";
}