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