g, c, p = map(int, input().split())
s = input()

ge, ce, pe = s.count('G'), s.count('C'), s.count('P')
pt = 0
#勝ち
gw = min(ce, g)
ce -= gw
g -= gw
cw = min(pe, c)
pe -= cw
c -= cw
pw = min(ge, p)
ge -= pw
p -= pw

pt += (gw + cw + pw) * 3

#あいこ
pt += min(ge, g) + min(ce, c) + min(pe, p)

print(pt)