def oi(): return int(input())
def os(): return input()
def mi(): return list(map(int, input().split()))

# import sys
# input = sys.stdin.readline
# import sys
# sys.setrecursionlimit(10**8)
# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')
input_count = 0

from itertools import groupby

# RUN LENGTH ENCODING str -> list(tuple())
# example) "aabbbbaaca" -> [('a', 2), ('b', 4), ('a', 2), ('c', 1), ('a', 1)] 
def runLengthEncode(S: str) -> "List[tuple(str, int)]":
    grouped = groupby(S)
    res = []
    for k, v in grouped:
        res.append((k, int(len(list(v)))))
    return res

input_count = 0
oi()
S = os()
def solve(S):
    dist = len(S)-S.index("#")-1

    run = runLengthEncode(S)
    if run[0][0] == "#":
        dist += run[0][1]
        ind = 1
    else:
        dist += run[1][1]
        ind = 2

    if run[-1][0] == ".":
        run = run[:-1]

    komi = 0
    if ind < len(run):
        for r in run[ind:]:
            if r[0] == ".":
                komi -= r[1]
            else:
                komi += r[1]
    dist += max(komi, 0)
    return (dist)

print(solve(S))