#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
string ans;
void solve(ll n){
    if(n==0) return;
    ll d=0;
    while((d+1)*(d+1)<=n) d++;
    char c;
    if(!ans.empty()) c='a'+(ans.back()-'a'+2)%26;
    else c='a';
    for(int i=0; i<2*d-1; i++){
        if(i&1) ans+=('a'+(c-'a'+1)%26);
        else ans+=c;
    }
    solve(n-d*d);
}
int main()
{
    ll n; cin>>n;
    solve(n);
    cout<<ans<<endl;
    return 0;
}