#include <complex>
#include <iomanip>
#include <iostream>
using namespace std;
int main() {
double num;
cin >> num;
double low,high,mid;
double epsilon = 0.01;//精度
if(num <= -1){
low = num;
high = 0;
}
else if(num >= 1){
low = 0;
high = num;
}
else if(num > -1 && num <0){
low = -1;
high = 0;
}
else{
low = 0;
high = 1;
}
while(high - low > epsilon){
mid = (high + low) / 2;
double midcube = mid * mid * mid;
if(std::abs(midcube - num) < epsilon * epsilon){
break;
}
if(midcube < num){
low = mid;
}
else{
high = mid;
}
}
double result = (high + low) / 2;
cout << fixed << setprecision(1) << result ;
}