prompt: Your task is to convert an English description into an ASCII tree format using this style:
  ```
  api
   +--plugins
   `--tasks
       `--bundling
  ```
  
  Convert this description:
  
  packages is a principal directory that houses 3 subdirectories: a, b and c.
  At the top level, 'a' encapsulates 1 subfolders: nested-a.
  Within directory hierarchy 'a → nested-a', Inside 'nested-a', you'll find it has no folders inside.
  At the top level, 'b' keeps 1 nested folders: nested-b.
  In nested path 'b > nested-b', The 'nested-b' collection has nothing inside.
  At the main level, The 'c' folder is blank.
  
  
  Provide your answer wrapped in <ascii_formatted> tags.
verification_info: {"ground_truth": "packages\n +--a\n |   `--nested-a\n +--b\n |   `--nested-b\n `--c", "description": "packages is a principal directory that houses 3 subdirectories: a, b and c.\nAt the top level, 'a' encapsulates 1 subfolders: nested-a.\nWithin directory hierarchy 'a \u2192 nested-a', Inside 'nested-a', you'll find it has no folders inside.\nAt the top level, 'b' keeps 1 nested folders: nested-b.\nIn nested path 'b > nested-b', The 'nested-b' collection has nothing inside.\nAt the main level, The 'c' folder is blank.\n"}