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(void){
int N;
scanf("%d\n", &N);
char S,tmp;
scanf("%1c", &S);
if(N == 1){
  printf("0");
  return 0;
}

int cnt = 0;
for(int i = 0; i < N; i++){
  scanf("%1c", &tmp);
  //printf("S = %c tmp = %c\n", S, tmp);
  if(S == '#' && tmp == '.'){
    cnt++;
    S = '#';
  }
  else{
    S = tmp;
  }
}
printf("%d",cnt);
}