A 42-year-old man from Delhi presents to the emergency department with acute onset ptosis, ophthalmoplegia affecting the medial rectus, and dilated pupil of the right eye. He reports severe right-sided headache for 2 days prior to symptom onset. Examination reveals proptosis and chemosis of the right eye. MRI brain with contrast shows a thrombosed right cavernous sinus with enhancement of the sinus walls. Which cranial nerve is LEAST likely to be involved in this patient's presentation?