f f a a x f f x a f a f a a 2.2 f f a a x f x a f f a a x f a f a a f f a a x f f x a f a f a a true f f a a x f f x a f a f a a f f a a x f x a true 2 1 a 0 20524 1 f 2 0 1 0 0 2 0 0 f 2 0 0 1 1 1 0 0 1 1 2 0 0 f f a a x f f x a f a f a a f f a a x f f x a f a f a a f f a a x f f x a f a f a a true 2 1 a 0 2 1 f 2 0 1 0 0 1 1 22591 f 2 0 0 1 0 1 1 0 0 0 2 0 0 f f a a x f f x a f a f a a f f a a x f a f a a false NaTT certifiable-1.6