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 JavaScript (Node.js 12.16.1) (judge verdict: Wrong Answer)

function Main(input) {
  // input = input.trim().split("\n").map(function(x) { return x.split(" ")});
  // let a = BigInt(input[0][0], 10);
  // let b = BigInt(input[0][1], 10);
  // let c = BigInt(input[0][2], 10);
  // let d = BigInt(input[0][3], 10);

  const text = input.split(" ").map(x => +x);
  const a = text[0],
        b = text[1],
        c = text[2],
        d = text[3];

  let ans = a * c;
  if (ans < a * d) ans = a * d;
  if (ans < b * c) ans = b * c;
  if (ans < b * d) ans = b * d;
  console.log(ans.toString());

}

// Main(require("fs").readFileSync("sample.txt", "utf8"));
Main(require("fs").readFileSync("/dev/stdin", "utf8"));