Problem:
Score : 300 points

Problem Statement

You are given four integers A, B, C, and D. Find the number of integers between A and B (inclusive) that can be evenly divided by neither C nor D.

Constraints

1\leq A\leq B\leq 10^{18}

1\leq C,D\leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C D

Output

Print the number of integers between A and B (inclusive) that can be evenly divided by neither C nor D.

Sample Input 1

4 9 2 3

Sample Output 1

2

5 and 7 satisfy the condition.

Sample Input 2

10 40 6 8

Sample Output 2

23

Sample Input 3

314159265358979323 846264338327950288 419716939 937510582

Sample Output 3

532105071133627368

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
int kansu(long int a,long int b,long int n)
{
  long int i;
  long int j;
  
  i=b/n;
  j=(a-1)/n;
  return i-j;
}

int main(void)
{
  long int a,b,c,d;
  long int n,m,nm;
  long int i,j;
  long int x;
  long int z=0;
  
  scanf("%d %d %d %d",&a,&b,&c,&d);
  
  n=kansu(a,b,c);
  m=kansu(a,b,d);
  
  for(i=a;i<=b;i++)
  {
    x=i;
    if(i%c==0)
     break;
  }
  for(i=0;i<n;i++)
  {
    if((x+i*c)%d==0)
      z++;
  }
  printf("%d",b-a+1-(n+m-z));
  
  return 0;
}