#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP(i,n,0)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)
#define INF 100000000

typedef long long ll;

int kr, kb;
string s;

int dfs(string ans, int n) {
    if (n == 30)
        return ans.size();
    else if (s[n] == 'R') {
        if (kr > ans.size() || ans[ans.size()-kr] != 'R')
            return max(dfs(ans+s[n],n+1),dfs(ans,n+1));
        else
            return dfs(ans,n+1);
    }
    else if (s[n] == 'B') {
        if (kb > ans.size() || ans[ans.size()-kb] != 'B')
            return max(dfs(ans+s[n],n+1),dfs(ans,n+1));
        else
            return dfs(ans,n+1);
    }
    else
        return dfs(ans+s[n],n+1);
}

int main() {
    cin >> kr >> kb >> s;
    cout << dfs("",0) << endl;
    return 0;
}