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: Accepted)

import java.util.*;
import java.io.*;

public class Main
{
	public static void main(String [] Args)
	{
		Scanner in=new Scanner(System.in);		
		long a=in.nextLong();
		long b=in.nextLong();
		long c=in.nextLong();
		long d=in.nextLong();
		long g=gcd(c,d);
		long q=c*d/g;
		long ans=b/c-(a-1)/c;
		ans=ans+b/d-(a-1)/d;
		ans=ans-b/q+(a-1)/q;
		ans=b-a-ans+1;
		System.out.println(ans);
	}
	
	public static long gcd(long a,long b)
	{
		if(a%b==0)
			return b;
		return gcd(b,a%b);
	}
}