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>
#define MIN(a,b) ((a<b)?(a):(b))
#define MAX(a,b) ((a>b)?(a):(b))
 
int main() {
    int n, i = 0, sharp = 0, dot = 0;
    char s[200001];
    scanf("%d %s", &n, s);

    while (s[i] == '.') {
        i++;
    }

    while(s[i]) {
        if (s[i] == '.') {
            dot++;
        } else {
            sharp++;
        }
        i++;
    }
    if (s[n-1] == '#') {
        sharp = MAX(0,sharp-1);
    }

    printf("%d", MIN(sharp, dot));
    
    return 0;
}