# Algorithm for this generalized assignment problem

I'm trying to find an algorithm for the following problem.

There are $$5$$ computer files with capacity $$18$$, $$23$$, $$12$$, $$125$$, $$45$$ MB respectively and there are $$4$$ hard disks with capacity $$25$$, $$73$$, $$38$$, $$156$$ MB. Each file has to be saved in one and only one disk. The cost of saving a file $$i$$ in a disk $$j$$ is the capacity of the disk $$j$$. Find an algorithm of saving files such that the total cost is minimum.

I think this problem can be reformulated as the Min-cost-max-flow problem. However, I don't know how to refomulate the condition "the sum of capacity of files in a disk cannot exceed the capacity of that disk". Can anyone help me? Thank you very much.