#include <iostream>
#include <vector>
#include <algorithm>

int main(){
    int r, b;
    std::cin >> r >> b;

    std::string S;
    std::cin >> S;

    std::vector<int> rs, bs;
    for(int i=0;i<30;i++){
        if(S[i] == 'R'){
            rs.push_back(i);
        }else if(S[i] == 'B'){
            bs.push_back(i);
        }
    }

    int res = 0;
    for(int i=0;i<1<<10;i++){
        for(int j=0;j<1<<10;j++){
            std::vector<int> indices;
            for(int k=0;k<10;k++){
                if(i >> k & 1){indices.push_back(rs[k]);}
                if(j >> k & 1){indices.push_back(bs[k]);}
            }

            std::sort(indices.rbegin(), indices.rend());

            std::string s = S;
            for(int index : indices){
                s.erase(s.begin() + index);
            }

            int l = s.size();
            bool f = true;
            for(int k=0;k<l;k++){
                if(s[k] == 'R' && (k-r >= 0 && s[k-r] == 'R' || k+r < l && s[k+r] == 'R')){
                    f = false;
                    break;
                }else if(s[k] == 'B' && (k-b >= 0 && s[k-b] == 'B' || k+b < l && s[k+b] == 'B')){
                    f = false;
                    break;
                }
            }

            if(f){res = std::max(res, l);}
        }
    }

    std::cout << res << std::endl;
}