#include <bits/stdc++.h>
using namespace std;
map<string, bool> mp;
int main() {
	int n;
	cin >> n;
	string s;
	bool vis = false;
	cin >> s;
	char ch = s[s.size() - 1];
	mp[s] = 1;
	for (int i = 2; i <= n; i++) {
		cin >> s;
		if (mp[s]||ch!=s[0]) {
			vis = true;
			break;
		}
		mp[s] = 1;
		ch = s[s.size() - 1];
	}
	if (vis)
		cout << "No";
	else
		cout << "Yes";
	return 0;
}