There are N stones arranged in a row. Every stone is painted white or black. A string S represents the color of the stones. The i-th stone from the left is white if the i-th character of S is `.`, and the stone is black if the character is `#`.  Takahashi wants to change the colors of some stones to black or white so that there will be no white stone immediately to the right of a black stone. Find the minimum number of stones that needs to be recolored.
n=int(input())
s=input()
b,w=0,0
for i in s:
    if i=="#":b +=1
    else:w +=1

print(min(b,w)-1 if s[-1]=="#" else min(b,w))
n=int(input())
s=input()
cnt=s.count(".")
ans=cnt
for i in s:
  if i==".":cnt -=1
  else:cnt +=1
  ans=min(ans,cnt)
print(ans)