#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;
    vector<int> v;
    for (int i = 29; i >= 0; i--) {
        if (n & (1 << i)) v.push_back(i);
    }
    if (v.size() == 1) {
        if (n == 1) cout << "a" << endl;
        else cout << string(v[0] * 2, 'a') << endl;
        return 0;
    }
    v.push_back(-1);
    string ans = "";
    for (int i = 1; i + 1 < v.size(); i++) {
        ans += string(v[i] - v[i + 1], (char)('a' + i));
    }
    string rans = ans;
    reverse(rans.begin(), rans.end());
    ans = rans + string((v[0] - v[1]) * 2, 'a') + ans;
    cout << ans << endl;
    return 0;
}