A 42-year-old female lives in the basement, is unemployed, undernourished. She complains of having general weakness, hair loss, brittle nails for six months, likes to eat chalk. Objectively: the patient is emaciated, pale, has dry skin. Peripheral lymph nodes are not enlarged. Liver is +1,5 cm. In blood: RBCs -1,8 × 1012/l, Hb- 62 g/l, colour index - 0,78, reticulocytes - 0,5o/oo, ESR - 18 mm/h. Leukogram exhibits no pathology. What is a provisional diagnosis?