#include<bits/stdc++.h>//万能头文件

using namespace std;

int main() {
    long double x;
    cin >> x;
    long double l = 0, r = x;
    while (r - l > 1e-6) {
        long double m = (l + r) / 2;
        if (m * m * m > x) {
            r = m;
        } else {
            l = m;
        }
    }
    printf("%.Lf", l);
    return 0;
}