import sys
#input = sys.stdin.readline
#input = sys.stdin.buffer.readline #文字列はダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
#from collections import defaultdict 
#from collections import deque
#import copy
#import math
#from functools import lru_cache
#@lru_cache(maxsize=None)
#MOD = pow(10,9) + 7
#MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]
#dx8 = [1,1,0,-1,-1,-1,0,1]
#dy8 = [0,1,1,1,0,-1,-1,-1]

def main():
    N = int(input())
    S = str(input())

    ans = N
    idx = 0
    while idx < N and S[idx] == '.':
        idx += 1
    ans -= idx

    if ans == 0:
        print(ans);exit()
    
    seq = 0
    lag = 0
    for i in range(idx,N):
        if S[i] == '#':
            lag += 1
        else:
            lag -= 1
        seq = max(seq, lag)
    
    ans += seq - 1
    print(ans)



if __name__ == '__main__':
    main()