a a x1 a b a x1 b a b x1 a c a x1 2.2 b a b x1 a x1 a a x1 a b a x1 b a b x1 a c a x1 a a x1 b a x1 true a a x1 b a x1 a a x1 a b a x1 b a b x1 a x1 true a 1 1 21240 b 1 1 0 c 1 0 a 1 1 21239 b 1 1 0 a a x1 a b a x1 a a x1 a b a x1 b a b x1 a c a x1 a a x1 a b a x1 true 2 1 a 1 1 1 0 0 1 6 1 b 1 0 0 1 1 1 3 1 c 1 1 1 a 1 1 0 1 0 1 0 0 b 1 0 0 a a x1 a b a x1 b a b x1 a c a x1 b a b x1 a c a x1 false NaTT certifiable-1.6