Ice skater — calculate revolutions per second?

Hello, I have a few ideas about how to solve this problem. Unfortunately, none of them lead anywhere. The problem is:

An ice skater with outstretched arms initially rotates at 1.1 revolutions per second. How many revolutions per second does she rotate at after she has pulled her arms toward her body? The moment of inertia of the upright body (without arms) is 5.3 kg⋅m^2. The combined moment of inertia of both outstretched arms is 8.1 kg⋅m^2, and the moment of inertia of both inwardly pulled arms is 1.8 kg⋅m^2.

Can someone help me? I need to get a value, a revolution per second, somehow. I'd really appreciate it. 🙂