#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
using namespace std;

int cnts[26];

int main() {
	int n; cin >> n;

	for (int i = 0; i < n-1; i++) {
		cout << "a";

		int x = i;
		while (x) {
			cout << char('a' + (x%26));
			x /= 26;
		}

		cout << "a";
		cout << endl;
	}
	cout << "an" << endl;

	return 0;
}