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 Go (1.6) (judge verdict: Runtime Error)

package main

import (
	"fmt"
	"bufio"
	"os"
)

func input() (s1 string, n int) {
	var tmp int
	fmt.Scan(&tmp)
	s := bufio.NewScanner(os.Stdin)
	s.Scan()
	s1 = s.Text()
	n = tmp
	return
}

func count(s string, n int) int64 {
	var m1 int64
	var m2 int64

	for i := 0; i<n; i++ {
		if s[i] == 35 {
			m1++
		} else {
			m2++
		}
	}
	if m1 >= m2 {
		return m2
	} else {
		return m1
	}
}

func main() {
	s, n := input()
	fmt.Println(count(s, n))
}