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) throws Exception {
		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;
		if(a < 0 && b <= 0 && c < 0 && d <= 0) {
			ans = a * c;
			System.out.print(ans);
		}else if(a < 0 && b <= 0) {
			if(c < 0) {
				ans = a * c;
				System.out.print(ans);
			}else{
				ans = b * c;
				System.out.print(ans);
			}
		}else if(c < 0 && d <= 0) {
			if(a < 0) {
				ans = a * c;
				System.out.print(ans);
			}else{
				ans = a * d;
				System.out.print(ans);
			}
		}else {
			ans = b * d;
			System.out.print(ans);
		}

		sc.close();
	}
}