#include <bits/stdc++.h>
#define rep(i,n) for(int i=(0);i<(n);i++)

using namespace std;

typedef long long ll;

int n;

void dfs(string s){
	n--;
	if(n == 0){
		cout << "an" << endl;
		exit(0);
	}

	rep(i, 26){
		cout << "a" << s << "a" << endl;
		s.push_back('a' + i);
		dfs(s);
		s.pop_back();
	}
}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin >> n;
	queue<string> q;
	q.push("");
	n--;
	while(n > 0){
		n--;
		string s = q.front();
		q.pop();
		cout << "a" << s << "a" << "\n";

		rep(i, 26){
			s.push_back('a' + i);
			q.push(s);
			s.pop_back();
		}
	}

	cout << "an" << endl;
}