She picks two $13$s, one $14$, three $15$s, five $19$s, and four $20$s.  The mode is $19.$  The median is $19.$  Thus, their difference should be $0.$ 
Amy picks some numbers as shown below:  $13, 20, 14, 15, 19, 20, 20, 19, 19, 15, 19, 19, 20, 13, 15$.  What is the difference between their mode and median? 
  - $$0$$ 
  - $$1$$ 
  - $$2$$ 
  - $$19$$ 
  - $$20$$ 