active f b c x mark f x x x active f x y z f x y active z active d m b f x y mark z mark f x y z active d mark c proper b ok b proper c ok c proper d ok d proper f x y z f proper x proper y proper z f ok x ok y ok z ok f x y z top mark x top proper x top ok x top active x 2.2 active f x y z active z proper f x y z proper z f x y mark z f x y z top ok x top active x f ok x ok y ok z f x y z active f b c x f x x x top mark x top proper x top ok x active x proper f x y z proper y proper f x y z f proper x proper y proper z active f x y z f x y active z top mark x proper x proper f x y z proper x true top ok x top active x top mark x top proper x true Failed! NaTT certifiable-1.6