import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
class Main19941 {
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringTokenizer st = new StringTokenizer(br.readLine());
int N = Integer.parseInt(st.nextToken());
int K = Integer.parseInt(st.nextToken());
String s = br.readLine();
boolean[] visited = new boolean[N];
int answer = 0;
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) == 'P') {
int startIdx = Math.max(i - K, 0);
int endIdx = Math.min(i + K, N - 1);
for (int j = startIdx; j <= endIdx; j++) {
if (s.charAt(j) == 'H' && !visited[j]) {
visited[j] = true;
answer++;
break;
}
}
}
}
System.out.println(answer);
}
}
휴지통/알고리즘 & 자료구조