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