What is the volume of the third balloon?

One balloon contains 2 Liters of Nitrogen at a pressure of 735 Torr. Another Balloon contains 1 Liter of Oxygen at a pressure of 1470 Torr. The gas from both balloons is transfered into a third balloon at a pressure of 2940 Torr. Assuming the temperature is 298 K in all Balloons, what will be the volume of the third balloon?