The war against Drupad

Dronacharya informs the Kauravas and the Pandavas that he and Ashwatthama will not be participating in the war. He also refuses to let Karna join this battle. Ashwatthama informs Duryodhan that Drupad's commander is immortal. How will the princes of Hastinapur defeat Drupad?Dronacharya informs the Kauravas and the Pandavas that he and Ashwatthama will not be participating in the war. He also refuses to let Karna join this battle. Ashwatthama informs Duryodhan that Drupad's commander is immortal. How will the princes of Hastinapur defeat Drupad?