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{
	public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	long a = scan.nextLong() - 1;
      	long b = scan.nextLong();
      	long c = scan.nextLong();
      	long d = scan.nextLong();
      	long g = gcd(c,d);
      	long l = c * d / g;
      	long countb, counta;
      	countb = b - b/c - b/d + b/l;
      	counta = a - a/c - a/d + a/l;
        
      	System.out.print(countb - counta);
    }
  	public static long gcd(long m , long n){
      if(n == 0){
      	return m;
      }
      else{
        	return gcd(n, m%n);
      }
    }
 
}