#include <iostream>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
using namespace std;

#define REP(i,n) for(int i=0; i<n; ++i)
#define FOR(i,a,b) for(int i=a; i<=b; ++i)
#define FORR(i,a,b) for (int i=a; i>=b; --i)
#define ALL(c) (c).begin(), (c).end()

typedef long long ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<VL> VVL;
typedef vector<VI> VVI;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;

int main() {
    ll n;
    cin >> n;
    string ans;

    if (n == 1){
        cout << "a" << endl;
        return 0;
    }

    VI d;
    ll hoge = n;
    while (hoge){
        d.push_back(hoge % 2);
        hoge /= 2;
    }
    reverse(ALL(d));

    // for (int x : d) cout << x;
    // cout << endl;

    VI a;
    int s = 0;
    FOR(i,1,d.size()-1){
        if (d[i] == 1){
            a.push_back(s);
            s = 0;
        }else{
            s++;
        }
    }
    a.push_back(s);

    // for (int x : a) cout << x << endl;

    REP(i,a.size()){
        char c = 'a' + (i % 26);
        int x;
        if (i == 0 || i == a.size() - 1){
            x = a[i] + 1;
        }else{
            x = a[i] + 2;
        }
        ans = string(x, c) + ans + string(x, c);
    }

    if (a.size() == 1) ans = string(2*a[0], 'a');
    cout << ans << endl;

    return 0;
}