Contest Duration: - (local time) (100 minutes) Back to Home
B - Product Max /

Time Limit: 2 sec / Memory Limit: 1024 MB

### 制約

• -10^9 \leq a \leq b \leq 10^9
• -10^9 \leq c \leq d \leq 10^9
• 入力はすべて整数

### 入力

a b c d


### 入力例 1

1 2 1 1


### 出力例 1

2


x=1,y=1 のとき x \times y=1x=2,y=1 のとき x \times y=2 であるため、答えは 2 です。

### 入力例 2

3 5 -4 -2


### 出力例 2

-6


### 入力例 3

-1000000000 0 -1000000000 0


### 出力例 3

1000000000000000000


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


### 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