#include <stdio.h>
#include <stdlib.h>
#include <fstream>
#include <cstring>
using namespace std;

int main()
{
    ifstream fin;
    ofstream fout;

    char str[501],
         str1[500];
    str[0] = 'a';
    char sign;
    int counter = 0;
    //int ocounter = 0;
    //int ccounter = 0;
    bool result = 1;

    fin.open("brackets.in");
    fout.open("brackets.out");
    fin >> str;
    while(str[0] != ' ')
    {
        /* if (str[0] != '(' && str[0] != '[')
        {
            result = 0;
            break;
        }*/

    for(int i = 0; i < strlen(str); i++)
    {


       sign = str[i];
       //fout << str1[counter - 1];
       if((sign == '(') || (sign == '['))
            str1[counter++] = sign;

       else if ((sign == ')' && str1[counter - 1] == '(') || ((sign == ']' && str1[counter - 1] == '[')))
       {
           counter--;
       }
       else if ((sign == ')' && str1[counter - 1] != '(') || ((sign == ']' && str1[counter - 1] != '[')))
       {
           result = 0;
           break;
       }
    }
    //fout << (result? "YES": "NO") << endl;
    str[501] = 'a';
    fin >> str;
    fout << str << endl;
    }



    return 0;
}