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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>

int main(){
  
  int n,i,count = 0,count1 = 0;
  scanf("%d",&n);
  char s[n+1],t[n+1];
  scanf("%s",s);
  
  for(i = 0;i < n;i++)
    t[i] = s[i];

  for(i = 0; i < n;i++)
    if(s[i] == '#' && s[i+1] == '.'){
      s[i+1] = '#';
      count++;
    }
  for(i = n - 1; i > 0;i--)
    if(t[i-1] == '#' && t[i] == '.'){
      t[i-1] = '.';
      count1++;
    }
  if(count > count1)
    printf("%d",count1);
  else
    printf("%d",count);
  return 0;
}