Ukraine Visa --Help Please (Kyiv)

I'm a U.S. citizen and retired teacher. I have an opportunity to share an apartment in Chigirin, Ukraine with a Ukrainian friend. My question is : What documents do I need to effectively stay in the Ukraine for six months? The Ukrainian Consulate' s web page says a passport is all that is necessary. Having lived in Russia and China, I would question the accuracy of that statement. Chigirin is approximately 5 hours Southeast of Kyiv in Chrkasky Oblast. Information form anyone in the Kyiv arrea would be greatly appreciated. If you would care to exchange information at length, m y alternate email address is Protected content
Best Regards to Everyone,
Rick.