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