#include <iostream>
using namespace std;
 
int main ()
{
    int n;
    cin>>n;
    int s=0;
    int t=0;
    int bs=0;
    while (s<n)
    {
        t++;
        bs=bs+t;
        s=s+bs;
    }
    if (s==n)
        cout<<t;
    else if (s>n)
        cout<<(t-1);
        
    return 0;
}