A 45-year-old man was brought by an ambulance into the emergency hospital. He complains of sudden pain in the lumbar area frequent painful urination, and vomiting Examination detects pain in the lumbar area. costovertebral angle tenderness, pain on palpation of kidneys and along the ureter on the right. Urine test: proteins, fresh erythrocytes, leukocytes. Make the provisional diagnosis: