Stop in Hong Kong and Beijing

Hello!

I have a one way ticket to Hong Kong in March from Los Angeles and will be there for 3 days. Then I have an onward one way ticket from Hong Kong to Beijing and will be in Beijing for 48 hours before leaving on a one way ticket from Beijing to Hong Kong then back to Los Angeles. I am a U.S. citizen with a valid passport. I was wondering if I need a visa or not? According to my understanding I do not believe I do, thank you in advance!