Just Math easy contest
The pupils from 10-B class decided in the autumn holiday to go on an excursion to the capital. Knowing the number of boys n and girls m, determine how many rooms you need to book in a hotel, if each room has k beds and it is forbidden to settle boys and girls together.
One line contains three numbers n, m, k (n, m, k ≤ 100).
Print one number - the number of rooms to book in the hotel.
6 12 3