import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;

public class Main {
	
	public static int score(char y, char f){
		if(y == f){ return 1;}
		else if(y == 'G' && f == 'C' || y == 'C' && f == 'P' || y == 'P' && f == 'G'){ return 3; }
		else { return 0; }
	}
	
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		final int G = sc.nextInt();
		final int C = sc.nextInt();
		final int P = sc.nextInt();
		
		final char[] S = sc.next().toCharArray();
		
		int[][][] DP = new int[G + 1][C + 1][P + 1];
		
		
		for(int i = 0; i <= G; i++){
			for(int j = 0; j <= C; j++){
				for(int k = 0; k <= P; k++){
					final int sum = i + j + k;
					
					if(i != G){ DP[i + 1][j][k] = Math.max(DP[i + 1][j][k], DP[i][j][k] + score('G', S[sum])); }
					if(j != C){ DP[i][j + 1][k] = Math.max(DP[i][j + 1][k], DP[i][j][k] + score('C', S[sum])); }
					if(k != P){ DP[i][j][k + 1] = Math.max(DP[i][j][k + 1], DP[i][j][k] + score('P', S[sum])); }
				}
			}
		}
		
		System.out.println(DP[G][C][P]);
	}
	
}