Competitions

# Just Math easy contest

# Sightseeing trip

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.

#### Input

One line contains three numbers **n**, **m**, **k** (**n**, **m**, **k** ≤ **100**).

#### Output

Print one number - the number of rooms to book in the hotel.

Input example #1

6 12 3

Output example #1

6