import java.util.Scanner;

public class Beth {

    public static void main(String[] args) {
        Scanner vstup = new Scanner(System.in);

        int cislo = Integer.parseInt(vstup.next());

        String zatvorky = vstup.next();


        long suma = 0;

        char[] charArray = zatvorky.toCharArray();
        for (int i = 0; i < charArray.length - 1; i++) {

            String s = "" + charArray[i] + charArray[i + 1];
            if (s.equals("()") ||
                    s.equals("))")
            ) {
                suma++;
            }
        }

        System.out.println(suma);




    }



}