#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

#define REP(i,s,e) for (i = s; i <= e; i++)
#define rep(i,n) REP (i,0,(int)(n)-1)
#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP (i,(int)(n)-1,0)
#define INF (int)1e8
#define MOD (int)(1e9+7)

typedef long long ll;

int main(void) {
    int n;
    cin >> n;
    char c = 'c';
    for (int i = 0; n > 0; i++) {
        if (n >= 1 + i / 2) {
            cout << (i % 2 ? 'b' : 'a');
            n -= 1 + i / 2;
        }
        else {
            cout << c;
            c = (c - 'c' + 1) % ('z' - 'c' + 1) + 'c';
            n--;
        }
    }
    cout << endl;
    return 0;
}