Problem:
Score : 200 points

Problem Statement

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.

Sample Input 1

4 8 2

Sample Output 1

3

There are three integers between 4 and 8, inclusive, that are divisible by 2: 4, 6 and 8.

Sample Input 2

0 5 1

Sample Output 2

6

There are six integers between 0 and 5, inclusive, that are divisible by 1: 0, 1, 2, 3, 4 and 5.

Sample Input 3

9 9 2

Sample Output 3

0

There are no integer between 9 and 9, inclusive, that is divisible by 2.

Sample Input 4

1 1000000000000000000 3

Sample Output 4

333333333333333333

Watch out for integer overflows.

Solution in C# (Mono 4.6.2.0) (judge verdict: Time Limit Exceeded)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace AtCode
{
    class Class1
    {
        static void Main(string[] args)
        {
            string Input = Console.ReadLine();
            string[] DivInput = Input.Split(' ');
            long a = Convert.ToInt64(DivInput[0]);
            long b = Convert.ToInt64(DivInput[1]);
            long x = Convert.ToInt64(DivInput[2]);
            long count = 0;
            for (long i = a; i <= b; i++)
            {
                if(i%x == 0)
                {
                    count++;
                    long num = b - i;
                    count += (b - i) / x;
                    break;
                }
            }
           
            Console.WriteLine(count);
        }
        

       
    }
    
}