The seats still free

Problem

For the field trip you rent vans with per_van seats, and only as many as you need: 10 people at 4 seats a van means three vans.

Write a function that takes how many people are going and how many fit in a van, and returns how many seats are still free in the vans you rented: how many more people you can invite without renting another one. If every van is full no seat is free, and if nobody is going none is.

Examples

• 10, 4 → 2

• Every van full

  12, 4 → 0

• A single van

  3, 5 → 2

Besides these, the challenge has hidden tests that are revealed when you submit your solution.

You start with this

def free_seats(people, per_van):
    pass

function freeSeats(people, perVan) {
}