rambless

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) { // 注意 while 处理多个 case
            cal(in.nextDouble());
        }
    }

    private static void cal(double val) {
        //-20 <= val <= 20
        double right = Math.max(val, 1);
        double left = Math.min(val, -1);
        double mid = 0;
        double temp;
        while(right-left>0.001) {
            mid = (right+left)/2;
            temp = mid*mid*mid;
            if(temp>val) {
                right = mid;
            }
            if(temp<val) {
                left = mid;
            }
        }
        System.out.printf("%.1f", mid);
    }
}