Given an array of length n, find the subarray of length k which have largest sum of values.

Input

The first line contains two integers n and k (k ≤ n ≤ 10⁵)

The second line contains n integers which are elements of the array, each integer has absolute values not exceed 10⁶, respectively.

Output

The sum of values in the subarray

Sample

Sample Input

6 3

-3 -4 -1 -2 -4 -1

Sample Output

-7

There are 4 large test cases and 16 small test cases. Student can use two nested loops to solve first 16 testcases and earn 80% score.