Problem: 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.

Examples

Input

3
#.#


Output

1


Input

3
.#


Output

1


Input

5
.##.


Output

2


Input

9
.........


Output

0

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;
 
public class Main {
 
    void solve() throws IOException {
        int N = ni();
        String s = ns();
        int numw = 0;
        int numb = 0;
        for (int i = 0; i < N; i++) {
            if(s.charAt(i)=='#')numb++;
            if(s.charAt(i)=='.')numw++;
        }
        int leftblack = 0;
        int rightwhite = numw;
        ArrayList<Integer> nchange = new ArrayList<>();
        nchange.add(leftblack+rightwhite);
        for (int i = 0; i <N; i++) {
            if(s.charAt(i)=='.'){
                rightwhite--;
            }else{
                leftblack++;
            }
            // System.out.println(leftblack);
            // System.out.println(rightwhite);
            nchange.add(rightwhite+leftblack);
        }
        int ans = Collections.min(nchange);
        out.println(ans);
    }

    final int mod = 1000000007;
    int mul(int x, int y){
        return (int)((x * 1L * y) % mod);
    }
    int add(int x, int y) {
        x += y;
        return x >= mod ? (x - mod) : x;
    }
    int sub(int x, int y){
        x = add(x,mod-y);
        return x >= mod ? (x - mod) : x;
    }
    String ns() throws IOException {
        while (!tok.hasMoreTokens()) {
            tok = new StringTokenizer(in.readLine(), " ");
        }
        return tok.nextToken();
    }
 
    int ni() throws IOException {
        return Integer.parseInt(ns());
    }
 
    long nl() throws IOException {
        return Long.parseLong(ns());
    }
 
    double nd() throws IOException {
        return Double.parseDouble(ns());
    }
 
    String[] nsa(int n) throws IOException {
        String[] res = new String[n];
        for (int i = 0; i < n; i++) {
            res[i] = ns();
        }
        return res;
    }
 
    int[] nia(int n) throws IOException {
        int[] res = new int[n];
        for (int i = 0; i < n; i++) {
            res[i] = ni();
        }
        return res;
    }
 
    long[] nla(int n) throws IOException {
        long[] res = new long[n];
        for (int i = 0; i < n; i++) {
            res[i] = nl();
        }
        return res;
    }
 
    static BufferedReader in;
    static PrintWriter out;
    static StringTokenizer tok;
 
    public static void main(String[] args) throws IOException {
        in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);
        tok = new StringTokenizer("");
        Main main = new Main();
        main.solve();
        out.close();
    }
}