#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iostream>
#include <queue>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;

int ret;
map<string,int> memo;

void solve(int Kr, int Kb, string S){
  if(ret > S.length()) return;
  if(memo.count(S) > 0) return;
  memo[S] = 1;

  
  
  bool flg = false;
  rep(i,S.length()){
    if(S[i] == 'R' && i+Kr<S.length() && S[i+Kr]=='R') flg = true;
    if(S[i] == 'B' && i+Kb<S.length() && S[i+Kb]=='B') flg = true;
  }
  if(flg){
    rep(i,S.length()){
      solve(Kr, Kb, S.substr(0,i) + S.substr(i+1));
    }
  }else{
    ret = max(ret, (int)(S.length()));
  }
}

int main(){
  int Kr, Kb;
  string S;
  cin >> Kr >> Kb;
  cin >> S;

  ret = 3;

  solve(Kr, Kb, S);

  cout << ret << endl;
  
  return 0;
}