Mrs. Delgаdо is а 68-yeаr-оld wоman admitted to the med-surg unit with a diagnosis of severe pneumococcal pneumonia. Her PCP orders Penicillin G Potassium 2,000,000 IV Piggyback (IVPB) every 4 hours. Using the medication label provided, how many milliliters (mL) of diluent will you add to the vial to achieve a concentration of 1,000,000 units/mL? Enter the number only.