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>
#include<string.h>
int main(void)
{
  int N;
  int K=0;
  char S[2*10*10*10*10*10];
  while(N<1||N>2*10*10*10*10*10)
  {
    scanf("%d",&N);
  }
  scanf("%s",S);
  //printf("a\n");
  for(int i=0;i<N-1;i++){
	   if(S[i]!=S[i+1] && S[i]!='.'){
      K++;
      printf("%d\n",i);
      printf("%c\n",S[i]);
      printf("%c\n",S[i+1]);
     }
  }
  printf("%d\n",K);
  return 0;
}