Help me in solving CSTRMCQ3 problem

My issue

in the first case ABB A serves first and losses so score is A=0,B=0
next turn goes to B and wins therefore score is A=0 and B=1 since next serve is B
and again B serves if B win score is A=0,B=2 if B loose score is A=0 and B=1
so the final score is not equal but it was given equal

Learning course: Strings using C
Problem Link: CodeChef: Practical coding for everyone

remember if the server scores then only he gets points or else the server becomes receiver and receiver becomes server.
now “ABB”
initially A is the server .
first A scores so A will get 1 point → A=1,B=0
then B scores so B becomes server and no one will get point . → A=1,B=0.
then B scores again so B will get one point → A=1,B=1.