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()
{
	int N=0;
	int i=0;
	int length=0;
	int count1=0;
	int count2=0;	
	char *str;
	
	str = (char *)malloc(200000+1);
	
	if (str == NULL) {
		return -1;
	}
	 
	scanf("%d",&N);
	scanf("%s", str);
	length=strlen(str);
	
	for(i=0;i<length;i++)
	{
		if(str[i]=='.')
		{
			count1++;
		}
		else
		{
			count2++;
		}
	}
	
	if(count1<count2)
	{
		printf("%d\n",count1);
	}
	else
	{
		printf("%d\n",count2);
	}
	return 0;
}