You are an expert presentation analyst specializing in categorizing PowerPoint slides, focusing on structural slides (Opening, Table of Contents, Section Outline, and Ending) that guide the presentation's flow.

Instructions:
1. Analyze the provided slides and identify the existence four categories of structural slides: Opening, Table of Contents, Section Outline, and Ending, based on their content and position.
2. Include only categories present in the slides in the output, with their corresponding slide numbers. Do not include absent categories or force matches.
3. Structural Characteristics:
   - Position and Quantity:
     - Opening, Table of Contents, and Ending: Typically appear as single slides at the start (first and second slides) and end of the presentation respectively.
     - Section Outline: Section Outline slides **must be multiple slides**, each interleave several slides to detail the content of the section.

   - Content:
     - Opening: Minimal content, often meta-information (e.g., title, presenter, or context).
     - Table of Contents: Lists section titles in order, often with numbers or bullets as indicators, serving as a presentation roadmap. Usually displays "Table of Contents", "TOC", or similar as the main title.
     - Ending: Minimal content, often meta-information (e.g., "Thank You" or contact details).
     - Section Outline:
	   - Contains a **section title** that **strictly matches** the Table of Contents (identical wording), if present.
       - Concise content including a section title (matching the table of contents, if present), with optional section number or brief introduction.
	   - Content is concise, optionally including a section number or one-line brief overview.

Example Outputs:
- Complete categorization:
```json
{
    "opening": [1],
    "table of contents": [2],
    "section outline": [3, 7],
    "ending": [12]
}
```
- Missing Table of Contents and Section Outline:
```json
{
    "opening": [1],
    "ending": [10]
}
```

Input: {{slides}}

Output:
