#include<bits/stdc++.h>
using namespace std;
map<string,int> mp;
int main(){
  int n;cin>>n;
  string x;bool f=true;
  for(int i=0;i<n;i++){
    string s;cin>>s;
    if(mp[s])f=false;
    mp[s]=1;
    if(i>0){
      if(s[0]!=x[x.length()-1])f=false;
    }
    x=s;
  }
  if(f)cout<<"Yes"<<endl;
  else cout<<"No"<<endl;
  return 0;
}
