#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
 
using namespace std;
 
#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
 
#define MOD 1000000007

int dp[301][301][301];

int main(){
  int g,c,p;
  cin>>g>>c>>p;
  string s;
  cin>>s;
  clr(dp,-1);
  dp[0][g][c]=0;
  rep(i,1,s.sz+1){
    rep(j,0,301){
      rep(k,0,301){
        if(dp[i-1][j][k]==-1)continue;
        if(s[i-1]=='G'){
          if(j-1>=0)dp[i][j-1][k] = max(dp[i][j-1][k],dp[i-1][j][k]+1);
          if(k-1>=0)dp[i][j][k-1] = max(dp[i][j][k-1],dp[i-1][j][k]);
          dp[i][j][k] = max(dp[i][j][k],dp[i-1][j][k]+3);
        }
        if(s[i-1]=='C'){
          if(j-1>=0)dp[i][j-1][k] = max(dp[i][j-1][k],dp[i-1][j][k]+3);
          if(k-1>=0)dp[i][j][k-1] = max(dp[i][j][k-1],dp[i-1][j][k]+1);
          dp[i][j][k] = max(dp[i][j][k],dp[i-1][j][k]);
        }
        if(s[i-1]=='P'){
          if(j-1>=0)dp[i][j-1][k] = max(dp[i][j-1][k],dp[i-1][j][k]);
          if(k-1>=0)dp[i][j][k-1] = max(dp[i][j][k-1],dp[i-1][j][k]+3);
          dp[i][j][k] = max(dp[i][j][k],dp[i-1][j][k]+1);
        }
      }
    }
  }
  cout << dp[s.sz][0][0] << endl;
  return 0;
}