How much milk to give?

Mummies, how do you calculate how much EBM/formula to give your LO? My baby girl is 3weeks 4days old. I am feeding her about 60ml every 2hrs, however KK doctor claim that she should drink 50ml only. I tried giving her 50ml but she will cry for more. Infact when I gave her 60ml, at times she wants more. What can I do?