from collections import Counter
g,c,p = map(int, raw_input().split())
ct = Counter(raw_input())
x = min(g, ct['C'])
g = max(0, g-x)
ct['C'] = max(0, ct['C']-x)
y = min(c, ct['P'])
c = max(0, c-y)
ct['P'] = max(0, ct['P']-y)
z = min(p, ct['G'])
p = max(0, p-z)
ct['G'] = max(0, ct['G']-z)
w = max(g, ct['G'])
w += max(c, ct['C'])
w += max(p, ct['P'])
print (x+y+z)*3 + w