Arrive at the scene within 2 hours, complete the core epidemiological information investigation within 4 hours, push core information such as positive cases, close contacts, sub-close contacts and other people to the provincial health code database and assign red codes within 6 hours. Close contacts will be made within 8 hours, and secondary close contacts should be separated and cleared dynamically, and a preliminary flow control report will be completed within 24 hours. It means 2+4+6+8.