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 {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		long a = in.nextLong();
		long b = in.nextLong();
		int c = in.nextInt();
		int d = in.nextInt();
		long cd = (long)c * (long)d / gcd(c,d);
		long ans_a = (a-1)/c + (a-1)/d - (a-1)/cd;
		long ans_b = b/c + b/d - b/cd;
		System.out.println(b-a+1-ans_b+ans_a);
		in.close();

	}
	
	//return gcd O(logN)
	public static int gcd(int num1,int num2) {
		if(num2==0) return num1;
		else return gcd(num2,num1%num2);
	}

}
