three days is basically enough. Shantou University, Nan 'ao Island, Mayu Island and CITIC Resort are actually just these places. Personally, I think Nan 'ao Island and Shantou University are worth visiting, as well as the Tropic of Cancer sign tower near Shantou University. In terms of food, you must not miss beef balls. There is a famous Fuhecheng on Jinsha Road.