#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    string ans = "a";
    char cur = 'a';
    bool flag = false;
    for (int i = 29; i >= 0; i--) {
        if (n & (1 << i)) {
            if (!flag) flag = true;
            else {
                ans = cur + ans + cur;
                cur++;
                ans = cur + ans + cur;
            } 
        } else {
            if (flag) {
                ans = cur + ans + cur;
            }
        }
    }
    cout << ans << endl;
    return 0;
}