Problem Statement

Given are $N integers A_1,\ldots,A_N$.
We will choose exactly K of these elements. Find the maximum possible product of the chosen elements.
Then, print the maximum product modulo (10^9+7), using an integer between 0 and 10^9+6 (inclusive).

Input

Input is given from Standard Input in the following format:
N K
$A_1 \ldots A_N$

Output

Print the maximum product modulo (10^9+7), using an integer between 0 and 10^9+6 (inclusive).

Constraints

• $1 \leq K \leq N \leq 2\times 10^5$
• $|A_i| \leq 10^9$

Sample Input 1

4 2
1 2 -3 -4

Sample Output 1

12

The possible products of the two chosen elements are 2, -3, -4, -6, -8, and 12, so the maximum product is 12.

Sample Input 2

4 3
-1 -2 -3 -4

Sample Output 2

1000000001

The possible products of the three chosen elements are -24, -12, -8, and -6, so the maximum product is -6.
We print this value modulo (10^9+7), that is, 1000000001.

Sample Input 3

2 1
-1 1000000000

Sample Output 3

1000000000

The possible products of the one chosen element are -1 and 1000000000, so the maximum product is 1000000000.

Sample Input 4

10 10
1000000000 100000000 10000000 1000000 100000 10000 1000 100 10 1

Sample Output 4

999983200

Be sure to print the product modulo (10^9+7).

见题面 Input 部分

见题面 Output 部分