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

#define REP(i, n) for(int i=0; i<(n); i++)

int N;
signed main()
{
    cin >> N;
    int remain = N;
    string ans = "";
    char c = 'a';
    while(remain) {
        int add = (int)sqrt(remain);
        REP(i,add*2-1) {
            ans += (i%2) ? c+1 : c;
        }
        c += 2;
        if (c >= 'y') c = 'a';
        remain -= pow(add, 2);
    }
    cout << ans << endl;
    return 0;
}