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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
public class Main
{
    public static void main(String[] args) 
    {
      Scanner s = new Scanner(System.in);
      long n = s.nextLong();
      char[] c = s.next().toCharArray();
        long ans =0;
        long a1=0;
      for(int i=0;i<n;i++)
      {
        if(c[i]=='#')
        {
            // c[i+1]='#';
            ans++;
        }
        else if(c[i]=='.')
        {
            a1++;
        }

      }


      System.out.println(Math.min(ans,a1));
    }

    

}