Problem Statement:
Rick is an esteemed member of the Association of Crazy Mathematicians. One crazy night he decided to count the number of multiples between any two given numbers. For example, he has just figured out that there are 3 multiples of 2 between 1 and 7 (2, 4 and 6 respectively). Being an esteemed computer programmer too, Rick has decided to write a program to carry out his task.

Input:
The input consists of multiple cases. Each input is of the form "A B C" where A, B and C are integers. Each line contains exactly one input case.

Input Constraints:
A, B and C are signed 32-bit integers.

Output:
For each input case, you should produce 1 line of output. Each output line should contain a single integer which equals the number of integers between A and B (both inclusive) which are multiples of C. If C is zero, do not output anything and exit.

Sample Input:
1 7 2
1 7 3
0 0 0

Sample Output for Sample Input:
3
2