#include <cstdio>
#include <iostream>
#include<cstring>
#include <pthread.h>
#include <thread>
using namespace std;

int main()
{
     double x;
     cin>>x;
     double l = 0,r = max(1.0,x);
     while(r-l>1e-6){
         double mid = (l+r)/2;
         if(mid*mid*mid>=x) r = mid;
         else l = mid;
     }
     printf("%ld",(long)l);
}