AT_abc468_b [ABC468B] Corridor Watch

You are given integers $ M,D $ and a string $ S $ of length $ M $ consisting of `G` and `.`. There are $ M $ cells arranged in a row from left to right, numbered $ 1 $ through $ M $ from the left. Some of the cells have a guardman standing on them. Specifically, a guardman stands on cell $ i $ if $ S_i= $ `G`, and no one stands on cell $ i $ if $ S_i= $ `.`. A cell whose distance from a cell with a guardman is at most $ D $ is watched by that guardman. That is, a cell $ x $ is watched by a guardman if there exists a cell $ i $ such that $ S_i= $ `G` and $ |x-i|\le D $ . Among the $ M $ cells, find the number of cells that are **not** watched.

The input is given from Standard Input in the following format: > $ M $ $ D $ $ S $

Output the answer.

### Sample Explanation 1 Only cell $ 4 $ is not watched. ### Sample Explanation 2 All cells are not watched. ### Constraints - $ 0\le D < M \le 100 $ - $ D $ and $ M $ are integers. - $ S_i $ is a string of length $ M $ consisting of `G` and `.`.