#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int point(int a, int b) {
	if((a + 2) % 3 == b)
		return 3;
	else if(a == b)
		return 1;
	else
		return 0;
}

int main() {
	int G, C, P;
	cin >> G >> C >> P;
	string S;
	cin >> S;
	vector<vector<vi> > dp(G+1, vector<vi>(C+1, vi(P+1, -1)));
	dp[G][C][P] = 0;
	for(int i = G; i >= 0; -- i)
	for(int j = C; j >= 0; -- j)
	for(int k = P; k >= 0; -- k) {
		int x = dp[i][j][k];
		if(x == -1) continue;
		int p = S.size() - (i + j + k);
		int a = S[p] == 'G' ? 0 : S[p] == 'C' ? 1 : 2;
//		cerr << i << ", " << j << ", " << k << ": " << x << endl;
		if(i > 0) amax(dp[i-1][j][k], x + point(a, 0));
		if(j > 0) amax(dp[i][j-1][k], x + point(a, 1));
		if(k > 0) amax(dp[i][j][k-1], x + point(a, 2));
	}
	int ans = dp[0][0][0];
	printf("%d\n", ans);
	return 0;
}