Calculating actual atomic m of copper isotope 65Cu (show how it was done cause i have more than one to do)?

copper used in electric wires comes in two flavors (isotopes): 63Cu and 65Cu. 63Cu has an atomic m of 62.9298 amu and an ubundanc of 69.09%. the other isotope, 65Cu has an abundance of 30.91%. the average atomic m between these two isotopes is 63.546 amu. calculate the actual atomic m of 65Cu. ( im guessing its 64.162 if i right then let me know and if im wrong tell me and let me know how to get the right answer )