#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<cmath>
using namespace std;

const double eps = 1e-9;


int main() {
	long double x; cin >> x;
	long double l = -10e15; long double r =10e15;
	while (r - l > eps) {
		long double mid = (l+r)/2;
		if (mid * mid * mid >= x)
			r = mid;
		else
			l = mid;
	}
	cout << floor(l);



	return 0;
}