file = open('22.txt')
s = file.readline()
l = 0
k = 0
ans = 10**10
for r in range(len(s)):
    if s[r] == '.':
        k += 1
    while k >= 7:
        if s[l] == '.':
            k -= 1
        l += 1
        ans = min(ans, r - l + 1)
print(ans)