#include<bits/stdc++.h>
using namespace std;
int n;string s,l=" ";map<string,bool>mp;bool f; 
int main(){
	cin.tie(0);
	ios::sync_with_stdio(0);
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>s;
		if(!f&&i&&s[0]!=l[l.size()-1]||mp[s])
			f=1;
		mp[s]=1;
		l=s;
	}
	if(f)cout<<"No";else cout<<"Yes";
}