#include <bits/stdc++.h>

using namespace std;

int main() {
	int n;
	cin >> n;
	set<string> w;
	string x;
	for (int i = 0; i < n; i++) {
		string y;
		cin >> y;
		if (i&&y[0] != x.back())
			goto pnz;
		if (!w.insert(y).second)
			goto pnz;
		x = y;
	}
	cout << "Yes" << endl;
	return 0;
pnz:
	cout << "No" << endl;
	return 0;
}
