G, C, P = map(int, input().split())
S = input()

point = 0
for s in S:
    if s == "G":
        if P > 0:
            point += 3
            P -= 1
        else:
            if G > 0:
                point += 1
                G -= 1
    elif s == "C":
        if G > 0:
            point += 3
            G -= 1
        else:
            if C > 0:
                point += 1
                C -= 1
    elif s == "P":
        if C > 0:
            point += 3
            C -= 1
        else:
            if P > 0:
                point += 1
                P -= 1

print(point)