How to how knwo number of team members? using PHP/MYSQL

Question

want to know total team members from a table. the calculation formula is: suppose total team is 15 team

Team A
team B=2
team C=2
Team D (those parent is B )=6
Team E those parent is C)=5
and Total Team A=15
Team B=8
Team C=7


how can calculate it.

table structure

uid
uname
uemail

usid (user parent id)

 

 

 

formula

 

when user B (uid) Added in this table then parent user A is automatically Added in usid column.
example
maria(uid=5) join via jon(uid=2) then

uid	uname	uemail	usid
5	maria	[email protected]	2