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