A 28-year-old man is brought to the emergency department 2 hours after a flame burn involving his face, anterior chest, bilateral forearms, and anterior thighs. On examination, the burned areas show erythema with blistering and severe pain on touch. Unburned skin blanches normally. His airway is patent, respiratory rate 24/min, heart rate 110/min, blood pressure 128/80 mmHg. Using the Rule of Nines, what is the approximate total body surface area (TBSA) burned?