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.hasNextDouble()) { // 注意 while 处理多个 case
            float a = (float)in.nextDouble();
            System.out.println(f(a));

        }
    }

    public static String f(float a) {
        int i;
        for (i = 3; i >= -3; i--) {
            if (i * i * i <= a) {
                //System.out.println(i);
                break;
            } else {
                continue;
            }
        }

        float fNum = i;
        while (true) {

            //System.out.println(fNum);
            if (fNum * fNum * fNum == a) {
                return String.format("%.1f",fNum);
            } else if (fNum * fNum * fNum > a) {
                return (fNum - 0.05f) * (fNum - 0.05f) * (fNum - 0.05f) <= a ? String.format("%.1f",fNum)  :
                       String.format("%.1f",fNum-0.1f);
            } else {
                fNum += 0.1f;
            }

        }
    }
}