The balance paid is not enough to deduct the arrears or the set withholding amount. Summer is a new generation of college students' dating APP created by the joint venture team of Peking University and Tsinghua University in June 20 17. Insufficient balance in summer's account means that the balance paid is not enough to deduct the arrears or the set withholding amount. The main function is to get to know students from different schools through the mode of "answering questions and making friends", and find friends and even lovers who are in tune with themselves through the blackboard wall, rabbit hole and many communication sections in the school.