A patient complains of general weakness, pain in the gums, halitosis. Objectively: the patient is pale, adynamic, body temperature is 38,5°C, submandibular lymph nodes are enlarged, painful on palpation. Interdental gingival papillae are inflamed, their tops are "detruncated", covered with gray-yellow necrotic incrustation. Radiography of alveolar process and blood count reveal no apparent changes. What is the most likely diagnosis?