a and b
YES!
a and c
YES!
a and a
fail.
b and c
YES!
b and a
YES!
b and b
YES!
b and a
fail.
c and a
YES!
c and b
YES!
c and a
fail.
a and b
YES!
a and a
YES!
a and a
fail.
b and a
YES!
b and a
fail.
a and a
YES!
a and c
YES!
a and b
YES!
a and c
fail.
a and c
YES!
a and b
YES!
a and c
fail.
c and b
YES!
c and c
YES!
c and  
fail.
b and c
YES!
b and  
fail.
c and  
fail.
629