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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<iostream> 
#include<cstring>
using namespace std;

int main() {

	int n;
	cin >> n;
	string s;
	cin >> s;
	int ans;
	ans = n;
	int i = n-1;
	int i2 = n - 1;
	int temp = 0;
	int temp2 = 0;
	int ans_temp=0;
	int j;

	int check_a=0, check_b=0;


	for (i2; i2 > 0; i2--) {
		if (s[i2] == '#' && s[i2 - 1] == '.') {
			temp2 = i2;
			break;
		}
	}
	for (j = 0; j < temp2; j++) {
		if (s[j] == '#') {
			ans_temp++;
			check_a = ans_temp;
		}
	}
	for (j = temp2; j < n; j++) {
		if (s[j] == '.') {
			ans_temp++;
			check_b = ans_temp;
		}
	}
	if (ans > ans_temp) {
		ans = ans_temp;
		ans_temp = 0;
	}






	for (j = 0; j < n; j++) {
		if (s[j] == '.') {
			ans_temp++;
		}
	}
	if (ans > ans_temp) {
		ans = ans_temp;
		ans_temp = 0;
	}

	for (j = 0; j < n; j++) {
		if (s[j] == '#') {
			ans_temp++;
		}
	}
	if (ans > ans_temp) {
		ans = ans_temp;
		ans_temp = 0;
	}



	for (i; i > 0; i--) {
		if (s[i] == '.' && s[i - 1] == '#') {
			temp = i;
			break;
		}
	}
	for (j = 0; j < temp; j++) {
		if (s[j] == '#') {
			ans_temp++;
		}
	}
	if (ans > ans_temp) {
		ans = ans_temp;
		ans_temp = 0;
	}



	

	

	cout << ans;






	return 0;
}