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 {
	
	
	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);
	}
	private static long lcm(long m, long n) {
	    return m * n / gcd(m, n);
	}
	
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		long a=sc.nextLong(),b=sc.nextLong();
		long c = sc.nextInt(),d=sc.nextInt();
		
		long l = lcm(c,d);
		a--;
		long ans1 = a-a/c-a/d+a/l;
		long ans2 = b-b/c-b/d+b/l;
		
		long ans = ans2-ans1;
		
		System.out.println(ans);
		
		
		
	}
		


}
