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 sc = new Scanner(System.in);

		long A = sc.nextLong()-1;
		long B = sc.nextLong();
		long C = sc.nextLong();
		long D = sc.nextLong();
		//最大公約数
		long plese = (C*D)/gcd(C, D);

		long n = (B-(B/C+B/D))+(B/plese);
		long m = (A-(A/C+A/D))+(A/plese);
		long anser = (n-m);
		System.out.println(anser);
	}
	private static long gcd(long a, long b) {
		if(b==0) {
			return a;
		}
		a = a%b;
		return gcd(b,a);
	}

}
