import java.util.*;
import java.io.*;

public class Main{
    public static void main(String[] args){
        Main m = new Main();
        m.input();
        m.solve();
    }

    int n;
    String s;
    String[] sp;
    public void input(){
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        s = sc.next();
        sp = s.split("");
        sc.close();
    }

    int count;
    public void solve(){
        for(int i = 0; i < n; i++){
            if(sp[i].equals("(")){
                count = 1;
                for(int j = i + 1; j < n; j++){
                    if(sp[j].equals("(")){
                        count++;
                    }else{
                        count--;
                    }
                    if(count == 0){
                        System.out.println(j + 1);
                        break;
                    }
                }
            }else{
                count = 1;
                for(int j = i - 1; j >= 0; j--){
                    if(sp[j].equals(")")){
                        count++;
                    }else{
                        count--;
                    }
                    if(count == 0){
                        System.out.println(j + 1);
                        break;                        
                    }
                }
            }
        }
    }

}