C = ["x"] + list(input()) + list(input()) + ["x"]
ans = 0
cnt = 0
flag = False
for i in range(1,len(C)):
    if C[i] == "o":
        flag = True
        if flag and C[i-1] == "o":
            cnt += 1
    else:
        if flag and cnt == 0:
            ans = max(ans,1)
        else:
            ans = max(ans,cnt+1)
        flag = False
        cnt = 0
print(ans)