Discussion on: Daily Challenge #240 - ATM

def solve(n):
    count = 0
    while n - 500 >= 0:
        n -= 500
        count += 1
    while n - 200 >= 0:
        n -= 200
        count += 1
    while n - 100 >= 0:
        n -= 100
        count += 1
    while n - 50 >= 0:
        n -= 50
        count += 1
    while n - 20 >= 0:
        n -= 20
        count += 1
    while n - 10 >= 0:
        n -= 10
        count += 1

    if n != 0:
        return -1

    return count