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>
int ans(int a,int b,int c,int d){
  if(a>=b&&a>=c&&a>=d)
    return a;
  else if(b>=a&&b>=c&&b>=d)
    return b;
  else if(c>=a&&c>=b&&c>=d)
    return c;
  else
    return d;
  
  
}
int main(){
  int a,b,c,d;
  scanf("%d%d%d%d",&a,&b,&c,&d);
  int aa=a*c,bb=a*d,cc=b*c,dd=b*d;
  printf("%d",ans(aa,bb,cc,dd));
   
  return 0;
}