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 <bits/stdc++.h>
using namespace std;

#if __has_include("print.hpp")
  #include "print.hpp"
#endif

#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define MOD 1000000007

typedef long long ll;
typedef pair<int, int> p;


int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);

  int n;
  string s;
  cin >> n >> s;
  int dot_num = 0;
  int sharp_num = 0;
  int res = 0;

  for (int i = 0; i < n; i++) {
    if(s[i] == '#'){
      sharp_num++;
    }else{
      dot_num++;
    }
  }

  if(sharp_num == 0 || dot_num == 0) {
    cout << 0 << endl;
    return 0;
  }

  for (int i = 0; i < n; i++) {
    if(s[i] == '.'){
      dot_num--;
    }
    if(s[i] == '#'){
      res = dot_num;
      break;
    }
  }

  int res2 = 0;

  for (int i = n-1; i >= 0; i--) {
    if(s[i] == '#'){
      sharp_num--;
    }
    if(s[i] == '.'){
      res2 = sharp_num;
      break;
    }
  }

  cout << min(res, res2) << endl;



}