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: Time Limit Exceeded)

import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int number=sc.nextInt();

		String str = new String();

		int smallest=10000;



			str=sc.next();

		
		int count;
		for(int j=0;j<number+1;j++) {

			count=0;

		//	k=j;
			for(int z=0;z<number;z++) {

				if(z<=number-j-1) {
					if(str.charAt(z)!='.')
					{count++;
					if(count>(number/2)) {
						break;
					}
					}
				}
				else {
					if(str.charAt(z)!='#') {
						count++;
						if(count>(number/2)) {
							break;}
					}
					}
				
				
				
				

			}

			if(count<smallest){
				smallest=count;

		}

	}
		System.out.print(smallest);

}
}