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.*;

public class Main {
	public static void main(String[] args) {
		long i,j;
		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());
		sc.close();
		long cd = c*d/gcd(c,d);
		long cnt = 0;
		cnt = b/c - (a-1)/c;
//		System.out.println(cnt);
		cnt += b/d - (a-1)/d;
//		System.out.println(cnt);
		cnt -= b/cd - (a-1)/cd;
//		System.out.println(cnt);
		System.out.println(b-a-cnt+1);
	}
	public static long gcd(long a, long b) {
		long t;
		while((t=a%b)!=0) {
			a = b;
			b = t;
		}
		return b;
	}
}
