import java.util.Scanner;

public class No161{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		int num_G = sc.nextInt();
		int num_C = sc.nextInt();
		int num_P = sc.nextInt();
		String[] S = sc.next().split("");

		int score = 0;
		for(int i = 0; i < S.length; i++){
			if(S[i].equals("G")){
				if(num_P > 0){
					num_P--;
					score += 3;
				}else if(num_G > 0){
					num_G--;
					score += 1;
				}else{
					num_C--;
				}
			}else if(S[i].equals("C")){
				if(num_G > 0){
					num_G--;
					score += 3;
				}else if(num_C > 0){
					num_C--;
					score += 1;
				}else{
					num_P--;
				}
			}else{
				if(num_C > 0){
					num_C--;
					score += 3;
				}else if(num_P > 0){
					num_P--;
					score += 1;
				}else{
					num_G--;
				}
			}
		}
		System.out.println(score);
	}
}