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.Scanner;

public class Main {
	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		int N = scanner.nextInt();
		String str = scanner.next();
		String[] S1 = new String[N];
		//int[] S2 = new int[N];
		int count = 0;

		for (int i = 0; i < N; i++) {
			String str2 = String.valueOf(str.charAt(i));
			S1[i] = str2;
		}

//		for (int i = 0; i < N; i++) {
//			if (S1[i].equals(".")) {
//				S2[i] = 1;
//			} else {
//				S2[i] = 0;
//			}
//		}

//		for (int i = 0; i < N; i++) {
//			if (S2[i] == 0) {
//				for (int j = i; j < N; j++) {
//					if (S2[j] == 1) {
//						count += 1;
//					}
//				}
//				break;
//			}
//		}
		
		for (int i = 0; i < N; i++) {
			if (S1[i].equals("#")) {
				for (int j = i; j < N; j++) {
					if (S1[i].equals(".")) {
						count += 1;
					}
				}
				break;
			}
		}

		System.out.println(count);

		//	for (int i = 0; i < N; i++) {
		//		System.out.println(S2[i]);
		//	}
	}
}