The problem of moving cornet

When you say cornet, you mean mobile group users. You can open a cornet as the general manager of the group and then allow the following people to join, but most people don't have the ability to open a cornet. Schools are generally open and can join directly. General schools have agents. 10 yuan gives them 5 yuan, and they can add it. If you are not in school, you can only add other schools. The cornet number is 3 yuan for 2000 minutes a month, but both parties will join this group, which is this small internal. This requires both people to make local calls. There is no such thing as adding a cornet. If you two are in the same group, for example, both of you are "Peking University", you can play for 2000 minutes if you are 88 or 89.