I can only write down 16 and cannot go further.
8 of
$f(x_{1},x_{2},x_{3})=0$
000 = 0
001 = 0
010 = 0
110 = 0
111 = 0
110 = 0
101 = 0
011 = 0
and
8 of
$f(x_{1},x_{2},x_{3})=1$
000 = 1
001 = 1
010 = 1
110 = 1
111 = 1
110 = 1
101 = 1
011 = 1
That's the maximum I can go. How do I proceed?