Hi, I have a ticket San Francisco - Shanghai (stay 18 days) - San Francisco.

Of course, this is not eligible for the 144 h visa exention. So what I plan to do is San Francisco - SH (144 h) - Bangkok (stay 6 days) and then Bangkok - Hangzhou and SH (arrive in Hangzhou and train to SH, 144 h in total) - flight to San Francisco. Is this possible? Thanks!