#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define pb(a) push_back(a)
#define pr(a) cout<<(a)<<endl
#define PR(a,b) cout<<(a)<<" "<<(b)<<endl
#define R cin>>
#define F first
#define S second
#define ll long long
bool check(int n,int m,int x,int y){return (x<0||x>=n||y<0||y>=m)?false:true;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;


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