#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

int main() {
	int N;
	cin >> N;
	vector<string> ans;
	
	REP(i, N - 1) {
		string cur = "a";
		int m = i;
		while (m > 0) {
			cur += m % 26 + 'a';
			m /= 26;
		}
		cur += "a";
		ans.emplace_back(cur);
	}
	ans.emplace_back("an");
	for (auto & s : ans) cout << s << '\n';
}