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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, k100).

Output

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

Time limit 1 second
Memory limit 128 MiB
Input example #1
6 12 3
Output example #1
6