a a b x1 b b a a x1 b a b x1 a a a a x1 2.2 b a b x1 a a a x1 a a b x1 b a a x1 a a b x1 a a x1 a a b x1 b b a a x1 b a b x1 a a x1 b a b x1 a a a a x1 a a b x1 a x1 b a b x1 a x1 true b a b x1 a x1 a a b x1 a x1 b a b x1 a a a a x1 b a b x1 a a x1 a a b x1 b a a x1 a a b x1 b b a a x1 a a b x1 a a x1 b a b x1 a a a x1 true Failed! NaTT certifiable-1.6