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.*;
import java.lang.*;

class Main{
    
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        long B = sc.nextLong();
        long C = sc.nextLong();
        long D = sc.nextLong();

        sc.close();
        long ans = 0;
        long g = (C*D) / gcd(C,D);
       // System.out.println(g);
        ans += ((B/C) - ((A-1)/C));        
       // System.out.println(ans);
        ans += ((B/D) - ((A-1)/D));
       // System.out.println(ans);
        ans -= ((B/g) - ((A-1)/g));

        System.out.println((B-A+1) - ans);

    }
    static long gcd (long a, long b){
        long temp;
        while((temp = a%b) != 0){
            a = b;
            b = temp;
        }
        return b;
    }
}
