Based on the story provided and the scoring criteria, here is the evaluation:

{
  "TragedyDegree": 1,
  "ComedyDegree": 3
}

Explanation:
- Tragedy Degree: The story has almost no tragic elements. Marla's journey is quite positive and filled with personal growth and achievements. Thus, it scores a 1.
- Comedy Degree: The story is relatively light-hearted with moments of personal joy and satisfaction, especially with Marla's success in building the bookshelf. However, it doesn't have strong comedic elements or an extremely happy ending that is emotionally delightful. Therefore, it fits well with a score of 3.
