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

static String next ( ) throws IOException { while ( st == null || ! st . hasMoreTokens ( ) ) st = new StringTokenizer ( input . readLine ( ) . trim ( ) ) ; return st . 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: (expression_statement (assignment_expression left: (identifier) right: (object_creation_expression type: (type_identifier) arguments: (argument_list (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) name: (identifier) arguments: (argument_list))))))) (return_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))