#include <bits/stdc++.h>
using namespace std;

int main(void) {
	int n;
	cin >> n;
	map<string, int> m;
	char last;
	for (int i = 0; i < n; i++) {
		string s;
		cin >> s;
		m[s]++;
		if (i == 0) last = s[s.size() - 1];
		if (i > 0 && (last != s[0] || m[s] == 2)) {
			cout << "No" << endl;
			return 0;
		}
		last = s[s.size() - 1];
	}
	cout << "Yes" << endl;
	return 0;
}
