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.*;
class Main{
	public static void main(String args[]){
    	Scanner sc = new Scanner(System.in);
      	int N = sc.nextInt();
        int c = 0; 
      	String S = sc.next();
      	String[] strls = S.split("");
      	for(int n = N-1;n >= 0;n--){
        	if(strls[n].equals(".") == true && n >0){
                 if(strls[n-1].equals("#") ==true){
                 	//strls[n]="#";
            		c++;
                 }
            }   
        }
        System.out.println(c);   
    }
}