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 (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <stdio.h>
int main()
{
    int x,y;
    int z;
    int a,b,c,d;
    printf("enter those value: ");
    scanf("%d%d%d%d",&a,&b,&c,&d);
    if((a*c)>(a*d)){
        x=a;
        y=c;
        z=x*y;
        printf("%d",&z);
    }
    else
    {
        x=a;
        y=d;
        z=x*y;
        printf("%d",z);
        
    }
    if((b*c)>(b*d))
    {
        x=b;
        y=c;
        z=x*y;
        printf("%d",z);
    }
    else
    {
        x=b;
        y=d;
        z=x*y;
        printf("%d",z);
    }
    if(x==y)
        printf("%d",z);
    return 0;
}