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.*;
class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		long a=sc.nextLong();
		long b=sc.nextLong();
		int c=sc.nextInt();
		int d=sc.nextInt();
		int count=0;
		long l=lcm(c,d);
		System.out.println(b-b/c-b/d+b/l-a+1+(a-1)/c+(a-1)/d-(a-1)/l);
	}

	private static long lcm(long m,long n){
		return m*n/gcd(m,n);
	}

	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);
	}
}