Tina wants to take group fitness classes at a nearby gym, but needs to start by selecting a membership plan. With the first membership plan, Tina can pay $37 per month, plus $3 for each group class she attends. Alternately, she can get the second membership plan and pay $35 per month plus $5 per class. If Tina attends a certain number of classes in a month, the two membership plans end up costing the same total amount. What is that total amount? How many classes per month is that?