computability – Reducably complete langauges

Let A ⊆ {0, 1}∗, and let Ac = {0, 1}∗ − A be the complement of A. Prove: If A is≤m-complete for CE, then
A join Ac is neither c.e. nor co-c.e.

c.e–> Computably enumerable

The join of two languages A, B ⊆ {0, 1}∗is
A join B = {x0 | x ∈ A} ∪ {y1 | y ∈ B}.