Hello I am having trouble with figuring out how to write a function for the following problem, I have to write a program that finds all possible

Hello 

I am having trouble with figuring out how to write a function for the following problem, I have to write a program that finds all possible combinations for these three guys (john,nick,stephen) to split a check. John only has $10 bills, nick only has $5 bills and stephen only has $2 bills. The point is for each of them to put a bill down until they reach the correct amount, they never go over.  I would like to try writing this recursively but i'm having trouble thinking of a simple way to solve this. 

thanks for the help!