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.*;
public 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();
		long E = C*D;
		long F = Math.max(C,D);
		long G = Math.min(C,D);
		for( long i=1; i*i<=G; i++ ){
			if( G%i==0 ){
				if( F%(G/i)==0 ){
					E = (C*D)/(G/i);
					break;
				}
				if( F%i==0 ){
					E = (C*D)/i;
				}
			}
		}    
		System.out.println( (B-A+1) - (B/C+B/D-B/E) + ((A-1)/C+(A-1)/D-(A-1)/E) );     
	}
}
