using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using Enu = System.Linq.Enumerable;

class Program
{
    int N;
    int[] A, B;
    int?[, ,] memo = new int?[301, 301, 301];

    void Solve()
    {
        A = reader.IntArray(3);
        B = reader.String().Select(c => "GCP".IndexOf(c)).ToArray();
        N = B.Length;
        int ans = Rec(0, A);
        Console.WriteLine(ans);
    }

    int Rec(int i, int[] rem)
    {
        if (i == N) return 0;
        if (memo[i, rem[0], rem[1]].HasValue) return memo[i, rem[0], rem[1]].Value;
        int res = 0;
        for (int hand = 0; hand < 3; hand++)
            if (rem[hand] > 0)
            {
                rem[hand]--;
                res = Math.Max(res, Eval(hand, B[i]) + Rec(i + 1, rem));
                rem[hand]++;
            }
        memo[i, rem[0], rem[1]] = res;
        return res;
    }

    int Eval(int a, int b)
    {
        return (a == b) ? 1 : ((a + 1) % 3 == b) ? 3 : 0;
    }



    Reader reader = new Reader(Console.In);
    static void Main() { new Program().Solve(); }
}

class Reader
{
    private readonly TextReader reader;
    private readonly char[] separator = { ' ' };
    private readonly StringSplitOptions removeOp = StringSplitOptions.RemoveEmptyEntries;
    private string[] A = new string[0];
    private int i;

    public Reader(TextReader r) { reader = r; }
    public Reader(string file) { reader = new StreamReader(file); }
    public bool HasNext() { return Enqueue(); }
    public string String() { return Dequeue(); }
    public int Int() { return int.Parse(Dequeue()); }
    public long Long() { return long.Parse(Dequeue()); }
    public double Double() { return double.Parse(Dequeue()); }
    public int[] IntLine() { var s = Line(); return s == "" ? new int[0] : Array.ConvertAll(Split(s), int.Parse); }
    public int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public int[][] IntGrid(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); }
    public string Line() { return reader.ReadLine().Trim(); }
    private string[] Split(string s) { return s.Split(separator, removeOp); }
    private bool Enqueue()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return Enqueue();
        A = Split(line);
        i = 0;
        return true;
    }
    private string Dequeue() { Enqueue(); return A[i++]; }
}