Score : 200 points
You are given nonnegative integers a and b (a ≤ b), and a positive integer x. Among the integers between a and b, inclusive, how many are divisible by x?
The input is given from Standard Input in the following format:
a b x
Print the number of the integers between a and b, inclusive, that are divisible by x.
4 8 2
3
There are three integers between 4 and 8, inclusive, that are divisible by 2: 4, 6 and 8.
0 5 1
6
There are six integers between 0 and 5, inclusive, that are divisible by 1: 0, 1, 2, 3, 4 and 5.
9 9 2
0
There are no integer between 9 and 9, inclusive, that is divisible by 2.
1 1000000000000000000 3
333333333333333333
Watch out for integer overflows.