Ksusha the Squirrel

题意翻译

有一只松鼠 $Ksusha$ ,它要穿过一条分为 $n$ 个区域的路，区域编号从左到右分别为 $1...n$ ，$Ksusha$ 站在区域 $1$ ，要去区域 $n$ 但是路上有些石头挡住了 $Ksusha$ 的去路， $Ksusha$ 痛恨石头，所以它不想待在有石头的区域里 由于 $Ksusha$ 保持锻炼，所以它可以从区域$i$ 直接跳到区域 $i+1$ , $i+2$ , $...$ , $i+k$ 帮助 $Ksusha$ 出点主意，判断它是否能走到路的尽头(注意,它不能站在石头上)

题目描述

Ksusha the Squirrel is standing at the beginning of a straight road, divided into $ n $ sectors. The sectors are numbered 1 to $ n $ , from left to right. Initially, Ksusha stands in sector 1. Ksusha wants to walk to the end of the road, that is, get to sector $ n $ . Unfortunately, there are some rocks on the road. We know that Ksusha hates rocks, so she doesn't want to stand in sectors that have rocks. Ksusha the squirrel keeps fit. She can jump from sector $ i $ to any of the sectors $ i+1,i+2,...,i+k $ . Help Ksusha! Given the road description, say if she can reach the end of the road (note, she cannot stand on a rock)?

输入输出格式

输入格式

The first line contains two integers $ n $ and $ k $ $ (2<=n<=3·10^{5},1<=k<=3·10^{5}) $ . The next line contains $ n $ characters — the description of the road: the $ i $ -th character equals ".", if the $ i $ -th sector contains no rocks. Otherwise, it equals "\#". It is guaranteed that the first and the last characters equal ".".

输出格式

Print "YES" (without the quotes) if Ksusha can reach the end of the road, otherwise print "NO" (without the quotes).

输入输出样例

输入样例 #1

2 1
..

输出样例 #1

YES

输入样例 #2

5 2
.#.#.

输出样例 #2

YES

输入样例 #3

7 3
.#.###.

输出样例 #3

NO