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: Time Limit Exceeded)

#include <stdio.h>


int main()
{
  
   long long int a,b,c,d,l,ans=0,minMultiple,n ;
   long long int n1,n2,n3,u,v,w,x,y,z;
   
   scanf("%lld %lld %lld %lld",&a,&b,&c,&d);
  n=b-a+1;
  u=a/c;
  if(a%c!=0)
  {
      u++;
  }
  v=b/c;
  n1=v-u+1;
  
  
   w=a/d;
  if(a%d!=0)
  {
      w++;
  }
  x=b/d;
  n2=x-w+1;
  
  minMultiple = (c>d) ? c : d;
    // Always true
    while(1)
    {
        if( minMultiple%c==0 && minMultiple%d==0 )
        {
            l=minMultiple;
            break;
        }
        ++minMultiple;
    }
  
  y=a/l;
  if(a%l!=0)
  {
      y++;
  }
  z=b/l;
  n3=z-y+1;
  
  ans=n1+n2-n3 ;

  
  ans=n-ans;
   printf("%lld",ans);
   
    
    return 0;
}