#python 3.5.2

C1 = input()
C2 = input()

cnt = 0
cnt_max = 0
for c in C1+C2:
    if c == 'x':
        cnt_max = max(cnt_max, cnt)
        cnt = 0
    if c == 'o':
        cnt += 1
print(max(cnt, cnt_max))