g a g b b f a a f a a g d 2.2 f a a g d g a g b b f a a g a b true g a g b true a 0 2 d 0 1 b 0 1 f 2 1 f 2 0 g 1 1 0 g 1 0 b 0 0 g a g b f a a g d b f a a g a b false b f a a false f a a g d false NaTT certifiable-1.6