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

int N;
vector<string> W;

int main()
{
	cin >> N;
	W.resize(N);
	for (int i = 0; i < N; ++i)
		cin >> W[i];
	bool b = true;
	for (int i = 1; i < N; ++i) {
		if (W[i - 1].back() != W[i].front() || count(W.begin(), W.end(), W[i]) != 1) {
			b = false;
			break;
		}
	}
	cout << (b ? "Yes" : "No") << endl;
	return 0;
}