static String next ( ) throws IOException {
  while ( tok == null || ! tok . hasMoreTokens ( ) ) {
    tok = new StringTokenizer ( in . readLine ( ) ) ;
  }
  return tok . nextToken ( ) ;
}

static String next ( ) throws IOException { while ( tok == null || ! tok . hasMoreTokens ( ) ) { tok = new StringTokenizer ( in . readLine ( ) ) ; } return tok . nextToken ( ) ; }
(method_declaration (modifiers) type: (type_identifier) name: (identifier) parameters: (formal_parameters) (throws (type_identifier)) body: (block (while_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (unary_expression operand: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) body: (block (expression_statement (assignment_expression left: (identifier) right: (object_creation_expression type: (type_identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))))) (return_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))