# abstract algebra – Get a unit in the ring of the integral group \$ mathbb {Z}[mathbb{Z}/5mathbb{Z}]\$

Get a non-trivial unit of the entire group ring $$mathbb {Z}[mathbb{Z}/5mathbb{Z}]$$. By non-trivial, I do not mean a group element.

Since, bruteforce does not seem possible here, I tried to guess what a unit should be, other than the elements of the group. But I failed in this attempt. I would appreciate any kind of help.

Thank you!