you = map(int,raw_input().split())

enemy = [0,0,0]

s = raw_input()

for i in s:
	if i == 'C':
		enemy[0] += 1

	elif i == 'P':
		enemy[1] += 1

	else :
		enemy[2] += 1

ans = 0

for i in range(3):
	t = min(you[i],enemy[i]) 
	ans += 3 * t
	you[i] -= t
	enemy[i] -= t



enemy = enemy[2:] + enemy[:2]

for i in range(3):
	ans += min(you[i],enemy[i])

print ans