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.*;

public class Main {

	static long gcd(long x,long y) {
		if (x<y)gcd(y,x);
		if (y%x==0)return x;		
		return gcd(y,x%y);
	}
	
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		long a=Long.parseLong(scan.next());
		long b=Long.parseLong(scan.next());
		long c=Long.parseLong(scan.next());
		long d=Long.parseLong(scan.next());
		
		long lcm=c*d/gcd(c,d);
		
		//a未満でｃでもｂでも割れない数
		--a;
		long ans1=a/c+a/d-a/lcm;
		ans1=a-ans1;
		//b以下でｃでもｂでも割れない数		
		long ans2=b/c+b/d-b/lcm;
		ans2=b-ans2;		
	
		System.out.print(ans2-ans1);
} 	
}
//end