I cant figure out where the singularities are on this Q!

Q: Use a large semicircular contour and the residue theorem to evaluate:

.

Lets call the integral above I.

Then I = residues of .

Then when i find these residues i sub them into to get the residues but i cant figure out what z should be. It SHOULD be and but i have no idea how to get those. I got and . Are those equivalent?!?