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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll n;
    cin >> n;
    auto f = [&](ll v){
        ll ok = 0, ng = 1 << 30, mid;
        while(ok + 1 < ng){
            mid = (ok + ng) / 2;
            if(mid * mid <=  v) ok = mid;
            else ng = mid;
        }
        return ok;
    };
    char c = 'a';
    string ans;
    while(n){
        ll v = f(n);
        n -= v * v;
        v = 2 * v - 1;
        for(int i = 0; i < v; i++){
            ans += (i & 1 ? c + 1 : c);
        }
        c += 2;
    }
    cout << ans << '\n';
}