#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;
#define INF 1e9

typedef struct{
	int to;
	int cap;
	int cost;
	int rev;
}edge;

//min cost : s->t (flow:f)
int min_cost_flow(vector<vector<edge> > &G, int s, int t, int f){
	const int N = G.size();
	int cost = 0;
	vector<int> prev_v(N,-1);
	vector<int> prev_e(N,-1);
	
	while(f>0){
		//min distance(cost based) search with SPFA
		vector<int> dist(N, INF);

		vector<int> cnt(dist.size(), 0);

		dist[s] = 0;
		prev_v[s] = s;
		queue<int> Q;
		auto my_push = [&](int node){
			Q.push(node);
			cnt[node]++;
		};
		auto my_pop = [&]() -> int{
			int ret = Q.front();
			cnt[ret]--;
			Q.pop();
			return ret;
		};
		my_push(s);
		while(!Q.empty()){
			int pos = my_pop();
			for(int i=0; i<G[pos].size(); i++){
				edge& E = G[pos][i];
				if(dist[E.to] > dist[pos] + E.cost && E.cap > 0){
					dist[E.to] = dist[pos] + E.cost;
					prev_v[ E.to ] = pos;
					prev_e[ E.to ] = i;

					if(cnt[ E.to ] == 0){
						my_push( E.to );
					}
				}
			}
		}


		//cannot achieved to "t" return -1
		if(dist[t]>=INF) return -1;

		
		//add cost of s->t with flow=d
		int pos=t;
		int d=INF;
		while(pos!=s){
			int i=prev_v[pos];
			int j=prev_e[pos];
			pos = i;
			d = min(d, G[i][j].cap);
		}
		
		pos = t;
		//cout << t ;
		while(pos!=s){
			int i=prev_v[pos];
			int j=prev_e[pos];
			G[i][j].cap -= d;
			G[ G[i][j].to ][ G[i][j].rev ].cap += d;
			//cost += G[i][j].cost * d;
			pos = i;
			//cout << " <- " << pos;
		}
		//cout << endl;
		cost += d * dist[t];
		f -= d;

		//f==0 then end
	}
	return cost;
}


void add_edge(vector<vector<edge> > &G, int from, int to, int cap, int cost){
	G[from].push_back((edge){to, cap, cost, (int)G[to].size()});
	G[to].push_back((edge){from, 0, -cost, (int)G[from].size()-1});
}

int main(){
	int G,C,P;
	cin >> G >> C >> P;
	
	string S;
	cin >> S;

	int n = S.size();

	vector<vector<edge>> Graph(n + 3 + 2);
	int s = n+3+0;
	int t = n+3+1;

	int g = n+0;
	int c = n+1;
	int p = n+2;

	for(int i=0; i<n; i++){
		if(S[i] == 'G'){
			add_edge(Graph, g, i, 1, 3-1);
			add_edge(Graph, c, i, 1, 3-0);
			add_edge(Graph, p, i, 1, 3-3);
		}else if(S[i] == 'C'){
			add_edge(Graph, g, i, 1, 3-3);
			add_edge(Graph, c, i, 1, 3-1);
			add_edge(Graph, p, i, 1, 3-0);
		}else if(S[i] == 'P'){
			add_edge(Graph, g, i, 1, 3-0);
			add_edge(Graph, c, i, 1, 3-3);
			add_edge(Graph, p, i, 1, 3-1);
		}
		add_edge(Graph, i, t, 1, 0);
	}

	add_edge(Graph, s, g, G, 0);
	add_edge(Graph, s, c, C, 0);
	add_edge(Graph, s, p, P, 0);

	int ans = 3*n - min_cost_flow(Graph, s, t, n);

	cout << ans << endl;

	return 0;
}