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();
		long C = in.nextLong();
		long D = in.nextLong();
		long cm = (B / C) - ((A - 1) / C);
		long dm = (B / D) - ((A - 1) / D);
		long lcm = C * D / gcd(Math.max(C, D), Math.min(C, D));
		long common = (B / lcm) - ((A - 1) / lcm);
		long ans = (B - (A - 1)) - cm - dm + common;
		System.out.println(ans);
		in.close();
	}

	private static long gcd(long m, long n) {
		long temp;
		while (m % n != 0) {
			temp = n;
			n = m % n;
			m = temp;
		}
		return n;
	}
}