import re
n = int(input())
s = str(input())

count = 0

while s.count("#.") != 0:
    t = re.subn("##.#", '####', s)
    s = t[0]
    count += t[1]
    t = re.subn(".#..", '....', s)
    s = t[0]
    count += t[1]
    t = re.subn(".#.#", '...#', s)
    s = t[0]
    count += t[1]
    t = re.subn("##..", '####', s)
    s = t[0]
    count += t[1] * 2
    t = re.subn("#.", '..', s)
    s = t[0]
    count += t[1]

print(count)