Cultural exchanges in China

Nowadays visa type F is harder to get and only get 30 days. But this summer exchange is last for 6 weeks. I have the invitation letter from the organization for the exchange program. If I only get 30 days and I have to extend it while I go to neighbour country, will it be extended or still not sure? Which one that I should apply, single entry/double entries/multiple entries so that I can longer my visa?
And what is the best solution for that case?
Thankyou very much