S1=list(input())
S2=list(input())
S3=S1+S2
x=[-1,14]
N=[]
for i in range(len(S3)):
    if (S3[i]=="x"):
        x.append(i)
    else:
        pass

x=sorted(x)
for i in range(len(x)-1):
    N.append(x[i+1]-x[i])

print(max(N)-1)