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