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# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
namespace KCLC
{
  class Program
  {
    static void Main()
    {
      string[] Input = Console.ReadLine().Split();
      int[] intInput = new int [Input.Length];
      for(int i = 0; i < Input.Length; i++)
      {
        intInput[i] = int.Parse(Input[i]);
      }
      Array.Sort(intInput);
      Array.Reverse(intInput);
      Console.WriteLine(intInput[0] * intInput[1]);
    }
  }
}