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