a a b b x b b b a a a x a c x c a x c b x b c x dup A' a b b x collapse A' a x A' a x collapse x y dup x collapse x y dup y 2.2 a c x a x a a b b x a a a x dup A' a b b x collapse A' a x A' a x dup A' a b b x a x a a b b x a a x dup A' a b b x a x c b x c x collapse x y dup y a c x c a x a a b b x a x collapse x y dup x true collapse x y dup x collapse x y dup y dup A' a b b x collapse A' a x A' a x true Failed! NaTT certifiable-1.6