text: class A {
  }
  class B extends A {
  }
  class C extends A {
  }
  class AA {
  }
  class BB extends AA {
  }
  class CC extends AA {
  }
  class DD extends BB {
  }
  class EE extends BB {
  }
  class FF extends CC {
  }
  class GG extends CC {
  }
  