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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

fun main(args: Array<String>){
    val n = readLine()!!.toInt()
    var s = readLine()!!
    var min = 99999
    var sum = 0
    var cnt = 0

    for(i in 0..n-1){
        if(s[i] == '.'){
            cnt++
        }
    }

    min = cnt

    for(i in 1..n/2){
        var cnts = 0
        var cntp = 0
        for(j in 0..i-1){
            if(s[j] == '#'){
                cnts++
            }
        }
        for(j in n-1 downTo i){
            if(s[j] == '.'){
                cntp++
            }
        }
        sum = cntp + cnts
        
        if(min > sum){
            min = sum
        }
    }
    println(min)
}