An assembly line records an integer load reading for each of n consecutive minutes. For a fixed window length k, consider every contiguous window of exactly k consecutive minutes (there are n - k + 1 of them, sliding by one minute each time). For each window, its "spike" is the MAXIMUM load reading inside that window.
Print the SUM of the spikes over all windows.
Input format
Line 1: two integers n and k.
Line 2: n space-separated integers, the load readings.
Output format
A single integer: the sum of the per-window maxima.
Constraints
- 1 <= k <= n <= 100000
- -1000000 <= each reading <= 1000000