+--> Fizika
  |   |--> 1A
  |   |--> 2A
  |   |--> 2C
  |   |--> 2D
  |   |--> 2E
  |   `--> 3D
  | | +--> 1A
  | | +--> 1C
  | | ---> 2A
  | | | +--> estr
  | | | +--> tmeh
  | | +--> 3A
  | | +--> 4A
  +--> TZK