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 C (Clang 10.0.0) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<string.h>

int main(void) {

	int a;
	int b;
	int c;
	int d;
	int x;
	int y;
	

	scanf("%d", &a);
	scanf("%d", &b);
	scanf("%d", &c);
	scanf("%d", &d);
	scanf("%d", &x);
	scanf("%d", &y);

	if (a <= x <= b <= y <= d)
	{
		printf("%d", x*y);
	}
	if (a <= x <= c <= y <= d)
	{
		printf("%d", x*y);
	}

	return 0;

}