#! /usr/bin/env python3

# from fractions import gcd
from math import gcd
from collections import Counter, deque, defaultdict
from heapq import heappush, heappop, heappushpop, heapify, heapreplace, merge
from bisect import bisect_left, bisect_right, bisect, insort_left, insort_right, insort
from itertools import accumulate, product, permutations, combinations, combinations_with_replacement

N = int(input())
S = input()

c = Counter(S)
print(max(0, c["#"] - 1))