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);
		
		// 入力
		long A = sc.nextLong();
		long B = sc.nextLong();
		long C = sc.nextLong();
		long D = sc.nextLong();
		
		long lcm = (C * D) / gcd(D, C);
		long b = B - (B/C) - (B/D) + (B/lcm);
		long a = (A-1) - ((A-1)/C) - ((A-1)/D) + ((A-1)/lcm);
		
		System.out.println(b-a);
	}		
	
	 private static long gcd(long a, long b) {
		    if (b == 0) {
		      return a;
		    }
		    return gcd(b, a%b);
		  }
}
