A solar array logs its hourly energy output for n consecutive hours. A maintenance report needs the busiest stretch: over every block of exactly k consecutive hours, find the one with the greatest total output and report that total.
Input format
Line 1: two integers n and k.
Line 2: n space-separated non-negative integers, the hourly outputs.
Output format
A single integer: the maximum sum of any k consecutive hourly outputs.
Constraints
- 1 ≤ k ≤ n ≤ 100000
- 0 ≤ each output ≤ 1000000