package no038;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int kr = sc.nextInt();
		int kb = sc.nextInt();
		char[] s = sc.next().toCharArray();
		int n = 30;
		int nr = 10, nb = 10;
		int ans = 0;
		for(int i=0;i<1<<nr;i++) {
			for(int j=0;j<1<<nb;j++) {
				StringBuilder sb = new StringBuilder();
				int r = 0, b = 0;
				for(int k=0;k<n;k++) {
					if (s[k] == 'R') {
						if ((i>>r&1) == 0) {
							sb.append(s[k]);
						}
						r++;
					}else if (s[k] == 'B') {
						if ((j>>b&1) == 0) {
							sb.append(s[k]);
						}
						b++;
					}else if(s[k] == 'W') {
						sb.append(s[k]);
					}
				}
				String t = sb.toString();
				if (isValidString(t, kr, kb)) {
					ans = Math.max(ans,t.length());
				}
			}
		}
		System.out.println(ans);
	}

	public static boolean isValidString(String t,int kr,int kb) {
		char[] s = t.toCharArray();
		int n = s.length;
		for(int i=0;i<n-kr;i++) {
			if (s[i] == 'R' && s[i+kr] == 'R') {
				return false;
			}
		}
		for(int i=0;i<n-kb;i++) {
			if (s[i] == 'B' && s[i+kb] == 'B') {
				return false;
			}
		}
		return true;
	}
}