/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2020.05.25 01:05:50
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;

int main() {
    int n;cin >> n;
    ll k = 0;
    while((k + 1) * (k + 6) / 2 + 1 <= n) {
        k++;
    }
    string s;
    ll cnt = k * (k + 5) / 2 + 1;
    for (int i = 0; i < k; i++) {
        s += "ab";
    }
    s += "a";
    ll k2 = 0;
    while((k2 + 1) * (k2 + 6) / 2 + 1 <= n - cnt) {
        k2++;
    }
    ll cnt2 = k2 * (k2 + 5) / 2 + 1;
    for (int i = 0; i < k2; i++) {
        s += "cd";
    }
    s += "c";
    for (ll i = cnt + cnt2; i < n; i++) {
        s += "e";
        i++;
        if (i < n) {
            s += "f";
            i++;
        }
        if (i < n) {
            s += "g";
            i++;
        }
    }
    //cout << s.size() << endl;
    cout << s << endl;
    return 0;
}