text: const express = require('express');
  
  const router = express.Router();
  
  router.use('/subtract', require('./subtract'));
  
  module.exports = router;
  
  
  // global swagger schema defs
  /**
   * @swagger
   * definition:
   *   errorSchema:
   *     properties:
   *       errorCode:
   *         type: string
   *       message:
   *         type: string
   *       details:
   *         description: Error details
   *         type: object
   */
  