using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Program
{
    class Program
    {
        static void Main(string[] args)
        {
            //Stack<int> stack = new Stack<int>();
            //stack.Push(5);
            //stack.Push(66);
            //Console.WriteLine(stack.Peek());
            //Console.ReadLine();
            //stack.Pop();
            //Console.WriteLine(stack.Peek());
            //Console.ReadLine();

            Stack<string> stack = new Stack<string>();
            string inmatning = Console.ReadLine();
            for (int i = 0; i < inmatning.Length; i++)
            {
                Convert.ToChar(inmatning[i]);
                //Convert.ToChar(inmatning);
                if (inmatning == "(") //|| (inmatning[i] == "{") || (inmatning[i] == "[") )
                {
                    stack.Push(inmatning[i]);
                }
                //if ((inmatning[i] = ")") || (inmatning[i] = "]") || (inmatning[i] = "}"))
                //{
                //    stack.Pop();
                //}
                //else
                //{

                //}
                Console.WriteLine(stack.Peek());
            }
            Console.ReadLine();

        }
    }
}