#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <string>

#define repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
#define var auto
#define mod 1000000007
#define inf 2147483647
#define nil -1
typedef long long ll;

using namespace std;

int inputValue(){
    int a;
    cin >> a;
    return a;
}

template <typename T>
void output(T a, int precision) {
    if(precision > 0){
        cout << fixed << setprecision(precision)  << a << "\n";
    }
    else{
        cout << a << "\n";
    }
}

// end of template

int cal(int n){
    n *= 2;
    double dsqn = sqrt((double)(n));
    return int(dsqn);
}

ll isqrt(ll n){
    ll l = 0;
    ll r = n + 1;
    int cnt = 0;
    while(cnt < 100){
        ll mid = (l + r) / 2;
        if (mid * mid < n) {
            l = mid;
        }
        else{
            r = mid;
        }
        cnt++;
    }
    if ((l + 1) * (l + 1) == n) {
        return l + 1;
    }
    return l;
}

string aba(char a, char b, ll n){
    string ret = "";
    if (n) {
        ret.push_back(a);
        rep(i, n - 1){
            ret.push_back(b);
            ret.push_back(a);
        }
    }
    return ret;
}

int main() {
    cin.tie(0);
    // source code
    string alp = "abcdefghijklmnopqrstuvwxyz";
    
    ll N;
    cin >> N;
    
    vector<ll> ret;
    
    for (int i = 0; N > 0; i++) {
        ret.push_back(isqrt(N));
        // output(ret[i], 0);
        N -= ret[i] * ret[i];
    }
    
    rep(i, ret.size()){
        if (!ret[i]) break;
        cout << aba(alp[(2 * i) % 26], alp[(2 * i + 1) % 26], ret[i]);
    }
    
    cout << endl;
    
    return 0;
}