#include <string>
#include <iostream>
using namespace std;
#include <boost/xpressive/xpressive.hpp>
using namespace boost::xpressive;

int main(int argc, char** argv)
{sregex parentheses = as_xpr('(') >> *(keep(+~(boost::xpressive::set='(',')'))|by_ref(parentheses)) >> ')';
// parentheses = '(' >> *(keep(+~(as_xpr('(')|')'))|by_ref(parentheses)) >> ')';
 string line;
 while (getline(cin, line))
 {sregex_iterator i(line.begin(), line.end(), parentheses);
  for (sregex_iterator ei; i!=ei; ++i)
  {smatch mr = *i;
 //  regex_search(line, mr, parentheses);
   for (int x = 0; x<mr.size(); ++x) cout << mr[x] << endl;}}
/*  {cout << mr[x] << endl; 
   for_each(mr.nested_results.begin(), mr.nested_results.end(),
            output_nested_results());}}*/
 return 0;}