Once. According to Zhihu's inquiry, on June 6, 200217 16, Qin Li, my dear guardian and Johnny cooperated to carry out various publicity, and Happy Camp was also broadcast, and it was time to sweep the building. Sweeping the building is: a building starts with the residents on the roof, knocks on the first floor, or visits an office building layer by layer. Others, such as job seekers and resumes, can also be called floor sweeps.