// editor1
import java.util.Scanner;
public class main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        String s = scan.nextLine();
        for(char ch : s.toCharArray()){
            if(ch != '(' && ch != ')'){
                System.out.println("Invalid input");
                return;
            }
        }
        Stack<Integer> stack = new Stack<>();
        stack.push(0);
        for(char ch : s.toCharArray()){
            if(ch == '('){
                stack.push(0);
            }
            else{
                int u = stack.pop();
                int v = stack.pop();
                stack.push(v + Math.max(2*u,1));
            }
        }
        System.out.println(stack.pop());
    }
}