Two 2.00kg balls are attached to the ends of a thin rod length 50.0cm and negligible mass. The rod is free to rotate about a horizontal axis at the center, without friction. With the rod horizontal, a 50.0 gram glob of putty drops onto one of the balls, hitting it with a speed of 3.00m/s and sticking to it.

Question

Two 2.00kg balls are attached to the ends of a thin rod length 50.0cm and negligible mass. The rod is free to rotate about a horizontal axis at the center, without friction. With the rod horizontal, a 50.0 gram glob of putty drops onto one of the balls, hitting it with a speed of 3.00m/s and sticking to it.
What is the angular velocity of the system just after the wad hits and sticks?

I'm supposed to use conservation of angular momentum to solve this.