color=input()
a=int(stone)
result=100000
counter=0
left=[]
right=[]
black = 0
white = 0
xxx=[]
yyy=[]
list=[]
list2=[]
for i in range(a):
    list.append(color[i])
for i in range(a):
	left=color[:i]
    right=color[i:]
	w=left.count('#')
    b=right.count('.')
    if result > w+b:
      result=w+b
print(result)