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

int main() {
	int n;
	cin >> n;
	vector<string> w;
	string s;

	for (int i = 0; i < n; i++) {
		cin >> s;
		if (i != 0 && (count(w.begin(), w.end(), s) || s.front() != w.back().back())) {
			cout << "No" << endl;
			return 0;
		}
		w.push_back(s);
	}
	cout << "Yes" << endl;
}