package linear;

import java.util.ArrayDeque;

import java.util.Deque;

import java.util.Scanner;

public class Pgss2 {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

String input = sc.nextLine();

String result = pre(input);

System.out.println(result);

}

public static String pre(String str) {

Deque<Character> stack = new ArrayDeque<>();

int count = 0;

for (char ch : str.toCharArray()) {

if (ch == '(') {

count++;

} else if (ch == ')') {

count--;

} else {

if (count == 0) {

stack.addLast(ch);

}

}

}

StringBuilder sb = new StringBuilder();

while (!stack.isEmpty()) {

sb.append(stack.removeFirst());

}

return sb.toString();

}

}