A 50-year-old patient complains of headache, itchy skin, and pain in the toes and muscles, especially during walking Objectively, the skin of the face has a red-cyanotic tint. Lymph nodes are not palpable. Pulse - 76/min. Blood pressure - 180/100 mm Hg. The lungs have no abnormalities. The borders of the heart are displaced to the left by 2 cm. The liver is +2 cm. The spleen is near the edge of the costal arch, dense and painless. Complete blood count: erythrocytes 6,3.1012/L, hemoglobin - 201 g/1., color index - 0.8, leukocytes - 10.5 109/L, eosinophils - 4%, band neutrophils - 7%, segmented neutrophils - 62%, lymphocytes 22%, monocytes 5%, platelets - 500. 109/L, ESR - 1 mm/hour, hematocrit - 55%, What is the most likely diagnosis in this case?