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>
#include<stdlib.h>

int main(void){
    int count=0;
    long long int N;
    scanf("%lld", &N);
    /*if(scanf("%lld", &N) == 1){
        exit(1);
    }*/
    char S[N];
    scanf("%s", S);
    /*if(scanf("%s", S) == 1){
        exit(1);
    }*/
    for(int i=0; i<N; i++){
        if(S[i] == '#'){
            if(S[i+1] == '.'){
                S[i+1] = '#';
                count++;
            }
        }
    }
    printf("%d\n", count);
    return 0;
}