A 37-year-old man complained about pain and a slight swelling emerging during eating in the left submaxillary area. Objectively: a painful elastic infiltration in the left submaxillary area. Mouth opening is not limited. Bimanual palpation in the area of mylohyoid groove revealed a compact movable oblong induration. Mucous membrane is unchanged. Duct of the left submandibular gland doesn’t excrete saliva. What is the most probable diagnosis?