import java.util.Scanner;
public class Hello{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        String a=sc.nextLine();
        if(a.length<1){
            System.out.println("Invalid input");
            return;
        }
        for(int i=0;i<a.length();i++){
            char ch=a.charAt(i);
            if(!Character.isLetter(ch) && ch!='(' && ch!=')'){
                System.out.println("Invalid input");
                return;
            }
        }
        int firstopen=a.indexOf('(');
        int lastclose=a.lastIndexOf(')');
        if(firstopen==-1 || lastclose==-1|| firstopen>lastclose){
            System.out.println(a.replace("(","").replace(")",""));
            return;
        }
        StringBuilder result=new StringBuilder();
        for(int i=0;i<a.length();i++){
            char ch=a.charAt(i);
            if(ch=='(' && i!=firstopen) continue;
            if(ch==')' && i!=lastclose) continue;
            result.append(ch);
        }
        System.out.println(result.toString());
    }
}