#include <bits/stdc++.h>

using namespace std;

int hoge(int x) {
	int ok = 1, ng = 32000;
	while (ng - ok > 1) {
		int mid = (ok + ng) / 2;
		if (mid * mid <= x) ok = mid;
		else ng = mid;
	}
	return ok;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	cin >> n;
	string ans = "";
	for (int i = 0; n > 0 ; i += 2) {
		int cnt = hoge(n);
		for (int j = 0; j < cnt * 2 - 1; j++) {
			ans += 'a' + (i + j % 2) % 26;
		}
		n -= cnt * cnt;
	}
	cout << ans << endl;
	return 0;
}