#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 1e5 + 1;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const long long LINF = 1e18;
void solve() {
  int n;
  cin >> n;
  int count = 0, i = 1;
  while (1) {
    if ((i * (i + 1)) / 2 <= n) {
      n -= (i * (i + 1)) / 2;
      count++;
      i++;
    } else
      break;
  }
  cout << count;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int tc = 1;
  for (int t = 1; t <= tc; t++) {
    solve();
  }
}
