#include <bits/stdc++.h>
using namespace std;
int a, b, c, n;
long long x;
long long kek(int i, int j, int k) {
  return (i * (i - 1) / 2 + j * (j - 1) / 2 + k * (k - 1) / 2);
}
int main() {
  cin >> n;
  if (n == 0) {
    cout << "ab";
    return 0;
  }
  if (n == 1) {
    cout << "aa";
    return 0;
  }
  double f = (double)sqrt(n) + 30;
  for (int i = 0; (double)i < f; i++) {
    for (int j = 0; (double)j < f; j++) {
      for (int k = 0; (double)k < f; k++) {
        if (kek(i, j, k) == n) {
          while (i--) cout << "a";
          while (j--) cout << "b";
          while (k--) cout << "c";
          return 0;
        }
      }
    }
  }
  return 0;
}
