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<iostream>
using namespace std;

int main()
{
  int a,b,c,d;
  cin>>a;
  cin>>b;
  cin>>c;
  cin>>d;
  
  long long int A[2];
  long long int B[2];
  
  A[0]=a;
  A[1]=b;
  
  B[0]=c;
  B[1]=d;
  
  int max=A[0]*A[0];
  int product;
  for(int i=0;i<2;i++)
  {
      for(int j=0;j<2;j++)
      {
          product=A[i]*B[j];
          if(product>max)
          {
          max=product;
          }
      }
  }
  cout<<max;
  return 0;
}