I,R=input,range
N,A,B=map(int,I().split())
S=I()+'0'
X=[]
c=0
w="con"
for s in S:
	if s==w[c%3]:c+=1
	else:X,c=X+[c//3],s=="c"
D=[0]+[-N]*N
L=1
for x in X:
	L+=x//A
	for i in R(L,-1,-1):
		for j in R(min(x//A,i)+1):D[i]=max(D[i],(x-A*j)//B+D[i-j])
print(max([[0,i+min(i,D[i])][D[i]>i-2]for i in R(L)]))