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 Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.*;
 
public class Main{
	public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	long a = scan.nextLong();
      	long b = scan.nextLong();
      	long c = scan.nextLong();
      	long d = scan.nextLong();
      	long g = gcd(a,b);
      	long countb = b;
      	long counta = a-1;
      	long l = c * d / g;
      	if(g == 1){
        	countb = countb - b/c - b/d;
          	counta = counta - a/c - a/d;
        }
      	else{
      	countb = countb - b/c - b/d + b/l;
      	counta = counta - a/c - a/d + a/l;
        }
      	System.out.print(countb - counta);
    }
  	public static long gcd(long m , long n){
      long r ;
      if(m % n == 0){
      	return n;
      }
      else{
        	r = m % n;
    	while( r != 0 ) {
            m = n;
            n = r;
          r = m % n;
        }
        return n;
      }
      
    }
 
}