#include <stdio.h>
#include <math.h>
int main()
{
    double n,m;
    double i=0.1;
    scanf("%lf",&n);
    if(n>0)
    {
        while(i*i*i<n)
        {
            i=i+0.01;
        }
        printf("%.1lf",i);
    }
    else
    {
        m=-n;
        while(i*i*i<m)
        {

            i=i+0.01;
        }
        printf("%.1lf",-i);
    }
}