Bob is raking leaves for some money!

After surveying $N$ houses on his street Bob has an estimation on the amount of money he'll be paid if he rakes a specific house. More specifically, raking the $i$-th house will earn him $C_i$ dollars. As Bob is very lazy, he will only select exactly $K$ consecutive houses to rake.

What is the maximum amount of money Bob can make after raking $K$ consecutive houses?

Input Specification

The first line of the input will contain two integers $N$ and $K$ $(1 \le K \le N \le 10^5)$, indicating the number of houses ligned up and the number of consecutive houses Bob will select.

The next line of the input will contain $N$ integers ranging from $0$ to $10^9$ inclusive. The $i$-th integer indicates the amount of money Bob can earn from raking the $i$-th house.

Output Specification

Output an integer, representing the maximum number of cash Bob can earn.

Subtasks

Subtask 1 [40%]

$1 \le K \le N \le 50$

Subtask 2 [60%]

No additional constraints.

Sample Input

6 2
1 2 3 1 0 4

Sample Output

5

Sample Explanation

Bob can rake the second and third house to get $2 + 3 = 5$ dollars. There are no better options that this.