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