PARSER_BEGIN(Q1)

class Q1 {


  /** Standard code to call the parser
   */
  public static void main(String args[]) {

    Q1 parser;

    System.out.println("Reading from standard input . . .");
    parser = new Q1(System.in);
    try {
      parser.s();
      System.out.println("Yes");
     } catch (TokenMgrError e) {   // Lexical error
      System.out.println("No");
     } catch (ParseException e) {  // Parsing error
      System.out.println("No");
     }
  }   /* End of function "main" */

}

PARSER_END(Q1)



/******************/
/***** TOKENS *****/
/******************/

SKIP : /* WHITE SPACE */
{
  " " 
| "\t"
| "\n"
| "\r"
| "\f"
}

TOKEN :
{
  < SEMI : ";" >
| < COLON : ":" >
| < COMMA : "," >
| < ID : (<LETTER>)+ >
| < #LETTER : ["a"-"z","A"-"Z"] >
}


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

void s () : {}
{
  d() <EOF> 
}

void d () : {}
{
  i() <COLON> <ID> [<SEMI> d()]
}

void i() : {}
{
  <ID> ( <COMMA> <ID> )*
}