A 25-year-old female farmer presents with pallor and fatigue for 1 year. CBC shows: RBC 2.0×10<sup>12</sup>/L, Hb 50g/L, WBC 7.6×10<sup>9</sup>/L (neutrophils 50%, lymphocytes 26%, eosinophils 14%), SF 10μg/L. Blood smear reveals increased central pallor of red blood cells. Diagnosed with iron deficiency anemia. If this patient requires surgical treatment for gastrointestinal tumor and needs parenteral iron therapy (weight 50kg), the total iron dose required is approximately: