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: Wrong Answer)

import java.util.*;

public class Main{
	public static void main(String[] $$) throws Exception {
		Scanner $ = new Scanner(System.in);
		long A = $.nextLong() - 1, B = $.nextLong(), C = $.nextLong(), D = $.nextLong(), lcm = LCM(C, D);
		System.out.println(B + " - " +  A);
		System.out.println(B / C + " - " + A / C);
		System.out.println(B / D + " - " + A / C);
		System.out.println(B / (C * D) + " - " + A / (C * D));
		System.out.println((B - A) - (B / C - A / C) - (B / D - A / C) + ((B / lcm) - A / lcm));
	}
	public static long LCM(long a, long b){
		long A = a, B = b;
		if (a < b){
			long c = a;
			a = b;
			b = c;
		}
		while(b > 0){
			a -= b;
			if (a < b){
				long c = a;
				a = b;
				b = c;
			}
		}
		return A * B / a
		/*
		4 9 2 3 -> 2
		10 40 6 8 -> 23
		314159265358979323 846264338327950288 419716939 937510582 -> 532105071133627368
		*/;
	}
}