answer will be 67
to find that their is no hard rule .i derive this by using my intuition by taking condition
like as n/2= x
then find ceiling function of x/3 and said to be y
then do x+y and got your answer
where n is no of vertices lets take our question for n=100 then u find x=n/2 so which is 50
then find y which is ceiling of x/3 so 50/3 =17=y so
then x+y= 50+17=67 answer