#include <iostream>

using namespace std;
int main()
{
    long long n;
    cin >> n;
    long long left = 0, right = n, middle = left+right >> 1, ans = middle;
    while (right - left > 1) {
        if (ans * ans * ans > n) {
            right = middle;
            middle = left+right >> 1;
            ans = middle;
        }
        else if (ans * ans * ans < n) {
            left = middle;
            middle = left+right >> 1;
            ans = middle;
        }
        else {
            cout << ans ;
            return 0;
        }
    }
    cout << ans ;
    return 0;
}