Goal:
    a : byte  b : byte  e : NoConfusion_byte a b
  ============================
   (noConfusion_byte_obligation_2 a b (noConfusion_byte_obligation_1 a b e) =
    e)


DEBUG:Going to execute:
fun H =>
             let ph := fresh "X" in
             let ph' := fresh "X" in
             destruct H as [H ph ph']