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# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp6
{
    class Program
    {
        static void Main(string[] args)
        {
            int N = int.Parse(Console.ReadLine());
            char[] S = Console.ReadLine().ToArray();
            int plaseCH = Array.IndexOf(S, '#');
            char[] newary = new char[S.Length - plaseCH];
            if (plaseCH == -1 || plaseCH == S.Length - 1) 
            {
                Console.Write('0');
            }
            else
            {
                Array.Copy(S, plaseCH, newary, 0, S.Length - plaseCH);
                int ans = newary.Count(n => n == '.');
                //Console.WriteLine(plaseCH);
                Console.Write(ans);
            }
            

            //System.Threading.Thread.Sleep(1000);

        }
    }
}