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 <stdio.h>

int main(void){
 int N;
 char S[200000];
 int kioku=2;
  int count=0;
  scanf("%d",&N);
  scanf("%s",S);
  
  for(int a=0;a<N;a++){
    if(S[a]=='.'&&kioku==1){
      S[a-1]='.';
      count+=1;
      }
  	if(S[a]=='.')
      kioku=0;
    else if(S[a]=='#')
      kioku=1;
  }
  printf("%d",count);
  
return 0;
}