Help with Physics question! A space probe is traveling in outer space with a momentum that has a magnitude of?

A space probe is traveling in outer space with a momentum that has a magnitude of 5.69 x 107 kg·m/s. A retrorocket is fired to slow down the probe. It applies a force to the probe that has a magnitude of 1.76 x 106 N and a direction opposite to the probe's motion. It fires for a period of 12.0 s. Determine the momentum of the probe after the retrorocket ceases to fire.|||im not sure im sorry