We are going on a 28-day cruise Jan 2024 from Singapore to Japan stopping in Hong Kong and Shanghai. I know Hong Kong is visa -free for US citizens. I've been reading about all kinds of visa-free policies for Shanghai (144-hour, 24-hour, Shanghai 15-day visa free). Can anyone advise on whether or not I need to go through the expensive process of getting a tourist visa for 2 days of touring off the ship?