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 scan = new Scanner(System.in);

		long A = scan.nextLong() - 1;
		long B = scan.nextLong();
		long C = scan.nextLong();
		long D = scan.nextLong();

		long tmp = (C * D) / gcd(C, D);
		long n = ((B - (B / C + B / D)) + (B / tmp));
		long m = ((A - (A / C + A / D)) + (A / tmp));

		System.out.println(n - m);
	}

	static long gcd(long a, long b) {
		if (b == 0) {
			return a;
		}
		a = a % b;
		return gcd(b, a);
	}
}