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()
{
	int n,i,t=0,num1=0,num2=0;
	char s[200000];
	scanf("%d",&n);
	scanf("%s",&s);
	for(i=0;i<n;i++)
	{
		if(s[i]=='#')
		{
			t=i;
			break;
		}
		else
			t++;

	}
	if(t==n-1)
		printf("0\n");
	else
	{
		for(i=t;i<n;i++)
		{
			if(s[i]=='.')
				num1++;
			if(s[i]=='#')
				num2++;
		}
		if(s[i-1]!='#')
		{
		    if(t+num1>num2+1)
				printf("%d\n",num2+1);
			else
				printf("%d\n",t+num1);
		}
		else
		{
			if(t+num1>num2)
				printf("%d\n",num2);
			else
				printf("%d\n",t+num1);
		}

		
	}
	return 0;
}