Hey! Any help will be greatly appreciated!

1. This is a 2 part question. I got the first part.

i)compute $\displaystyle \Pi (S^1VS^2)$

I know how to do this one, the answer is Z, but I don't get how to do part 2 of the problem.

ii) describe all its covering spaces and the corresponding subgroups of $\displaystyle \Pi_1 $

Thank you!