Problem:
Score : 300 points

Problem Statement

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.

Constraints

1 \leq N \leq 2\times 10^5

S is a string of length N consisting of . and #.

Input

Input is given from Standard Input in the following format:

N
S

Output

Print the minimum number of stones that needs to be recolored.

Sample Input 1

3
#.#

Sample Output 1

1

It is enough to change the color of the first stone to white.

Sample Input 2

5
#.##.

Sample Output 2

2

Sample Input 3

9
.........

Sample Output 3

0

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

n = int(input())
s = input().rstrip()

count = 0

result1 = s.count('#')
result2 = s.count('.')


for x in s:
    count += 1
    if x != '.':
        break
    
    
result3 = s[count:].count('.')
result4 = s[count:].count('#') + 1


sorted(s,reverse = True)
count = 0

for x in s:
    count += 1
    if x != '#':
        break
    
result5 = s[count:].count('#')
result6 = s[count:].count('.') + 1
print(result1,result2,result3,result4,result5,result6)