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) {

		try (Scanner sc = new Scanner(System.in)) {

			long a = sc.nextLong();
			long b = sc.nextLong();
			long c = sc.nextLong();
			long d = sc.nextLong();

			long cd = c * d / gcd(c, d);

			long s = 0;
			long t = 0;
			long u = 0;

			if (a % c == 0) {
				s = b / c - a / c + 1;
			} else {
				s = b / c - a / c;
			}

			if (a % d == 0) {
				t = b / d - a / d + 1;
			} else {
				t = b / d - a / d;
			}

			if (a % cd == 0) {
				u = b / cd - a / cd + 1;
			} else {
				u = b / cd - a / cd;
			}

			long result = (b - a + 1) - (s + t - u);

			System.out.println(result);
		}

	}

	private static long gcd(long m, long n) {
		if (m < n)
			return gcd(n, m);
		if (n == 0)
			return m;
		return gcd(n, m % n);
	}

}
