G,C,P = map(int,raw_input().split(' '))#GCP
S = raw_input()
win = 0
drow = 0
b = [False for i in range(len(S))]
for s in range(len(S)):
	if S[s] == 'G' and P > 0:
		win += 1
		P -=1
		b[i] = True
	if S[s] == 'C' and G > 0:
		win += 1
		G -=1
		b[i] = True
	if S[s] == 'P' and C > 0:
		win += 1
		C -= 1
		b[i] = True
for i in range(len(S)):
	if b[i]:
		continue
	if S[i] == 'G' and G > 0:
		drow += 1
		G -= 1
	if S[i] == 'C' and C > 0:
		drow += 1
		C -= 1
	if S[i] == 'P' and P > 0:
		drow += 1
		P -=1
count = win * 3 + drow
print count