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 sc = new Scanner(System.in);
  	long[] nums=new long[4];
  	for(int i=0;i<4;i++){
  		nums[i]=sc.nextLong();
  	}
  	long e,g=0;
  	long n1=nums[2],n2=nums[3];
  	
  	while(g==0){
  		if(n2%n1==0){
  			g=n1;
  		}else{
  			e=n1%n2;
  			n1=n2;
  			n2=e;
  		}
  	}
  			
  	long f=(nums[1]-(nums[1]/nums[2]+nums[1]/nums[3]-nums[1]/(nums[2]*nums[3]/g)))-(nums[0]-1-((nums[0]-1)/nums[2]+(nums[0]-1)/nums[3]-(nums[0]-1)/(nums[2]*nums[3]/g)));
  	System.out.print(f);
  }
}