Between a and b ...

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?

Constraints

• 0 ≤ a ≤ b ≤ 10^{18}
• 1 ≤ x ≤ 10^{18}

Input

The input is given from Standard Input in the following format:

a b x

Output

Print the number of the integers between a and b, inclusive, that are divisible by x.

Examples

Input

4 8 2

Output

3

Input

0 5 1

Output

6

Input

9 9 2

Output

0

Input

1 1000000000000000000 3

Output

333333333333333333

inputFormat

Input

The input is given from Standard Input in the following format:

a b x

outputFormat

Output

Print the number of the integers between a and b, inclusive, that are divisible by x.

Examples

Input

4 8 2

Output

3

Input

0 5 1

Output

6

Input

9 9 2

Output

0

Input

1 1000000000000000000 3

Output

333333333333333333

样例

4 8 2

3