import numpy as np
n=2
a=[input() for i in range(n)]
N=int(a[0])
S=list(a[1])

kazuXD=0
flg=0
kazu=0
for i in range(N):
  if flg==0:
    if S[i]==".":
      kazu+=1
    else:
      flg=1
flg=0
for i in range(N):
  if i>=kazu:
    if S[i]==".":
      S[i]="#"
      kazuXD+=1
  
print(kazuXD)