An acid elution stain was made using a 1-hour postdelivery maternal blood sample. Two thousand cells were counted and thirty of these cells appeared to contain fetal hemoglobin. It is the policy of the medical center to add one vial of Rh immune globulin to the calculated dose when the estimated volume of the hemorrhage exceeds 20 mL of whole blood. Calculate the number of vials of Rh immune globulin that would be indicated under these circumstances