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.awt.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
import java.util.List;

public class Main {
    public static void main(String args[]) throws IOException {
        Scanner sc = new Scanner(System.in);
        long a=sc.nextLong();
        long b=sc.nextLong();
        long c=sc.nextInt();
        long d=sc.nextInt();
        long x=b-a+1 - ((b/c) - (a/c) + (b/d) - (a/d) - ((b/(lcm(c,d))) - (a/(lcm(c,d)))));
//        System.out.println(x);
        if (a%c==0)x--;
        if (a%d==0)x--;
        if (a%(lcm(c,d))==0)x++;
        System.out.println(x);

    }
    static long gcd(long a,long b){
        if(a==0)return b;
        else return gcd(b%a,a);
    }
    static long lcm(long a,long b){
        return (a*b)/gcd(a,b);
    }

}

