Problem:
Score : 300 points

Problem Statement

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.

Sample Input 1

4 9 2 3

Sample Output 1

2

5 and 7 satisfy the condition.

Sample Input 2

10 40 6 8

Sample Output 2

23

Sample Input 3

314159265358979323 846264338327950288 419716939 937510582

Sample Output 3

532105071133627368

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
public class Main {
	 public static long gcd(long x,long y){
        if(x < y) return gcd(y, x);
        if(y == 0) return x;
        return gcd(y, x % y);
    }
    public static long lcm(long x,long y){                                                              
        return x*y/gcd(x,y);                                                                                                                                                                                                                
    }
    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 = b/c;
        long f = b/d;        
        long g = b/lcm(c,d);
        long h = (a-1)/c;
        long i = (a-1)/d;        
        long j = (a-1)/lcm(c,d);
		System.out.println(b-e-f+g-a+1+h+i-j);
	}
}