//https://ncode.syosetu.com/n4830bu/254/
#include <bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin >> N;
    string ans;
    char c = 'a';
    for (long long len = 1e5 + 1; len >= 1; len -= 2) {
        long long maine = (len + 1) * (len + 1) / 4;
        if (N >= maine) {
            N -= maine;
            for (int i = 0; i < len; i++) {
                ans += c + (i % 2);
            }
            c += 2;
            len += 2;
        }
    }
    cout << ans << endl;
}