Problem:
Score : 200 points

Problem Statement

Given are integers a,b,c and d.
If x and y are integers and a \leq x \leq b and c\leq y \leq d hold, what is the maximum possible value of x \times y?

Constraints

-10^9 \leq a \leq b \leq 10^9

-10^9 \leq c \leq d \leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

a b c d

Output

Print the answer.

Sample Input 1

1 2 1 1

Sample Output 1

2

If x = 1 and y = 1 then x \times y = 1.
If x = 2 and y = 1 then x \times y = 2.
Therefore, the answer is 2.

Sample Input 2

3 5 -4 -2

Sample Output 2

-6

The answer can be negative.

Sample Input 3

-1000000000 0 -1000000000 0

Sample Output 3

1000000000000000000

Solution in Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		long a = sc.nextLong();
		long b = sc.nextLong();
		long c = sc.nextLong();
		long d = sc.nextLong();

		long ans = 0;
		long x, y;
		long xm, ym;

		if(Math.abs(a) > Math.abs(b)) {
			x = a;
			xm = b;
		}else {
			x = b;
			xm = a;
		}

		if(Math.abs(c) > Math.abs(d)) {
			y = c;
			ym = d;
		}else {
			y = d;
			ym = c;
		}

		if(x < 0 && y < 0) {
			ans = x * y;
		}else if(x > 0 && y > 0) {
			ans = x * y;
		}else {
			ans = xm * ym;
		}

		System.out.print(ans);
		sc.close();
	}
}