Physics Problem Help?

Three portions of the same liquid are mixed in a container that prevents the exchange of heat with the environment. Portion A has a m m and a temperature of 96.0 �C, portion B also has a m m but a temperature of 82.0 �C, and portion C has a m mC and a temperature of 34.0 �C. What must be the m of portion C so that the final temperature Tf of the three-portion mixture is Tf = 59.0 �C? Express your answer in terms of m; for example, mc = 2.20 m.