/* We store the output expression in a string as it's built up, and then
 * print this out when we're finished parsing
 */


options {
  LOOKAHEAD=1;
}


PARSER_BEGIN(Q3pre)

public class Q3pre {

  /*** Main routine - just call parser ***/
  public static void main(String args[]) throws ParseException {
    Q3pre parser = new Q3pre(System.in);
    try {
      parser.inp_line();
      System.out.flush();
    } catch (ParseException x) {
      System.out.println("Exiting due to parse error.");
      throw x;
    }
  }

}

PARSER_END(Q3pre)


SKIP : /*** Ignoring spaces/tabs ***/
{
    " "
  | "\t"
}

 
TOKEN : 
{
  < NUMBER : ( ["0"-"9"] )+ >
}


/*************************/
/***** GRAMMAR RULES *****/
/*************************/


void inp_line() :
{
  String e;
}
{
  e=expr() ( <EOF> | "\n" | "\r")
  { System.out.println(e); }
}

String expr() :
{
  String t1, t2;
}
{
  t1=term() ( "+" t2=term() { t1="+ "+t1+t2; } )*
  { return t1; }
}

String term() :
{
  String f1, f2;
}
{
  f1=factor() ( "*" f2=factor() { f1="* "+f1+f2; } )*  
  { return f1; }
}

String factor() :
{
  String e;
}
{
  <NUMBER> { return (token.image+" "); }
| "(" e=expr() ")"  { return e; }
}