#include <bits/stdc++.h>
#define pb push_back
#define sz(a) int(a.size())
#define re return
using namespace std;
int main()
{
	int w;
	cin>>w;
	string s;
	char a;
	int kg=0;
	set<string>cf;
	for (int i=0;i<w;i++)
	{
		cin>>s;
		if (i && s[0]!=a)  kg=1;
		a=s[sz(s)-1];
		cf.insert(s);
	}
	if (sz(cf)!=w)  kg=1;
	if (kg==0)  cout<<"Yes";
	else  cout<<"No";
	re 0;
}
