A 45-year-old woman complains about unbearable pain attacks in the left part of face lasting 1-2 minutes. Such attacks are provoked by mastication. These symptoms appeared 2 months ago after exposure to cold. Objectively: the pain is localized in the ending points of trigeminus on the left. A touch near nose wing provokes another pain attack and tonic spasm of face muscles. What is the most probable diagnosis?