Continuously ticket number

Hello everyone. I need your help. Suppose that I have 9 services. There is no prefix for any services. And all services under the root service. I want to print continuously ticket number when customer get ticket. For example when one customer choose service_a the ticket number will be 1. And then second customer comes and gets service_b. Instead of numbering from 1 I want to print 2. If someone choose service_c it will print 3. Shortly when we choose one service always ticket number increase. I want to do the same thing.

I found. Just change numbering type from 1 to 0 in net table.

Try to use admin app. It will be much conveniently.