Combinations

Create a function that takes a variable number of arguments, each argument representing the number of items in a group. The function should return the number of permutations (combinations) of choices you would have if you selected one item from each group.

Examples

combinations(2, 3) ➞ 6

combinations(3, 7, 4) ➞ 84

combinations(2, 3, 4, 5) ➞ 120

Notes

• Don't overthink this one.
• Input may include the number zero.