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: Runtime Error)

function prod(nums) {
	let input = nums.split(' ').map(BigInt);
  	let prod1 = input[0] * input[2];
	let prod2 = input[1] * input[3];
  	let prod3 = input[0] * input[3];
  	let prod4 = input[1] * input[2];
	let res = [prod1, prod2,prod3, prod4].sortsort((a, b) => (a < b) ? -1 : ((a > b) ? 1 : 0));
	return res[0];
}
 
console.log(prod(require("fs").readFileSync("/dev/stdin", "utf8")));