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

	public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = Long.parseLong(sc.next());
        long b = Long.parseLong(sc.next());
        long c = Long.parseLong(sc.next());
        long d = Long.parseLong(sc.next());
        a -= 1;

        long lcm = c * d / gcd(c,d);
        long n = b - (b/c) - (b/d) + (b/lcm);
        long m = a - (a/c) - (a/d) + (a/lcm);
        System.out.println(n-m);
	}
}
