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