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 (Clang 3.8.0) (judge verdict: Time Limit Exceeded)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
int main(int argc,char *argv[]){
  int h;
  int w;
  char isrd = 1;
  long long mon1;
  long long mon2;
  long long mon3;
  char tla[10];
  int i = 0,j=0,k=0,l=0;
  int goukei=0;
  long loopc=0;
  long long lc=0;
  long a[10000],b[10000];
  long apoint=0,bpoint=0;
  
  scanf("%ld",&mon1);
  scanf("%ld",&mon2);
  scanf("%ld",&mon3);
  for(i = mon1;i <= mon2;i++){
    if(i == 0){
      lc++;
      continue;
    }
    if((i % mon3) == 0){
      lc++;
    }
  }
  printf("%d",lc);
  return 0;
}