#!/usr/bin/env python3
#fileencoding: utf-8

ren = 0
cur = 0
for i in "".join([input().strip() for i in range(2)]):
    if i == "x":
        if cur > ren:
            ren = cur
        cur = 0
    else:
        cur += 1
if ren < cur:
    ren = cur
print(ren)