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: Wrong Answer)

package main

import (
	"fmt"
	"strings"
)

func main() {
	s, c := SingleInt(), SingleStr()
	strs := strings.Split(c, "")
	strs = append(strs, "#")
	l := len(strs)

	co := make([]int, 0, s)
	var conv int
	var hit bool
	for i := 0; i < l; i++ {
		if strs[i] == "." {
			conv++
		}
		if strs[i] == "#" {
			hit = true
			co = append(co, conv)
			conv = 0
		}
	}

	var re int
	if !hit {
		fmt.Printf("%#v\n", re)
	}
	for _, v := range co {
		re += v
	}
	fmt.Printf("%#v\n", re)
}

func SingleInt() int {
	var n int
	fmt.Scan(&n)
	return n
}

func SingleStr() string {
	var s string
	fmt.Scan(&s)
	return s
}