#include <bits/stdc++.h>
using namespace std;

int main() {
    int N; cin >> N;
    char a = 'a', b = 'b';
    while (N > 0) {
        int n = sqrt(N);
        N -= n * n;
        for (int i = 0; i < n - 1; i++)
            cout << a << b;
        cout << a;
        a += 2; b += 2;
    }
    cout << endl;
}