a,b,c=map(int,input().split())
s=input()
ca,cb,cc=0,0,0
for i in range(len(s)):
	if s[i]=='G':ca+=1
	if s[i]=='C':cb+=1
	if s[i]=='P':cc+=1
out=0
t=min(a,cb)
out+=t
a-=t
cb-=t
t=min(b,cc)
out+=t
b-=t
cc-=t
t=min(c,ca)
out+=t
c-=t
ca-=t
print(out+min(a,ca)+min(b,cb)+min(c,cc))