#include <cstdio>
#include <cstring>
#include <algorithm>

int dp[301][301][301];
char S[310];

// i: p, j: o
int battle(char c, char d){
    if(c == 'G' && d == 'C' ||
       c == 'C' && d == 'P' ||
       c == 'P' && d == 'G'){
        return 3;
    }
    if(c == d){return 1;}
    return 0;
}

int main(){
    int G, C, P;
    scanf("%d %d %d", &G, &C, &P);

    scanf("%s", S);

    int L = strlen(S);

    std::fill(&dp[0][0][0], &dp[0][0][0]+301*301*301, -1001001001);
    dp[0][0][0] = 0;
    for(int i=0;i<L;i++){
        for(int j=0;j<=G;j++){
            for(int k=0;k<=C;k++){
                int l = i - (j + k);
                if(l < 0 || l > P){continue;}

                if(j+1 <= G){
                    dp[i+1][j+1][k] = std::max(dp[i+1][j+1][k], dp[i][j][k] + battle('G', S[i]));
                }
                if(k+1 <= C){
                    dp[i+1][j][k+1] = std::max(dp[i+1][j][k+1], dp[i][j][k] + battle('C', S[i]));
                }
                if(l+1 <= P){
                    dp[i+1][j][k] = std::max(dp[i+1][j][k], dp[i][j][k] + battle('P', S[i]));
                }
            }
        }
    }

    int res = 0;
    for(int j=0;j<=G;j++){
        for(int k=0;k<=C;k++){
            res = std::max(res, dp[L][j][k]);
        }
    }

    printf("%d\n", res);
}