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.

Examples

Input

4 9 2 3


Output

2


Input

10 40 6 8


Output

23


Input

314159265358979323 846264338327950288 419716939 937510582


Output

532105071133627368


import java.util.Scanner;

public class Main {
	   static long gcd(long a, long b) 
	    { 
	    if (a == 0) 
	        return b;  
	    return gcd(b % a, a);  
	    } 
	      
	    // method to return LCM of two numbers 
	    static long lcm(long a, long b) 
	    { 
	        return (a*b)/gcd(a, b); 
	    } 
	static long find(long x,long c,long d)
	{
		long ans=0;
		ans=x/d;
		ans+=x/c;
		ans-=x/lcm(c,d);
		return ans;
	}
	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 ans=(b-find(b,c,d))-((a-1)-find(a-1,c,d));
		System.out.println(ans);
	}
}
