#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001



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