#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int n, level = 0, counter = 0;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    counter += i;
    n -= counter;
    if (n < 0) break;
    level++;
  }
  cout << level << endl;
  return EXIT_SUCCESS;
}
