1 A A A A A A A A A A A A A A A A A A A A 2 B
    1 A A A A A A A A A A A A A A A A A A A A 2 B 3 C
    1 A A A A A A A A A A A A A A A A A A A A 2 B 3 C
    1 A A A A A A A A A A A A A A A A A A A A 2 B
      2.1 a a a a a a a a a a a a a a a a a a a a 2.2 b
    3 C