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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.Scanner;

class LCM {
    static long lcm(int a, int b){
        return (long)a * b / gcd(a, b);
    }

    private static int gcd(int a, int b){
        if(b == 0){
            return a;
        }else{
            return gcd(b, a % b);
        }
    }
}

public class Main {
    static Scanner stdIn = new Scanner(System.in);
    public static void main(String[] args){
		long a = stdIn.nextLong();
		long b = stdIn.nextLong();
		int c = stdIn.nextInt();
		int d = stdIn.nextInt();
		System.out.println(antiDivision(a, c, d));
		System.out.println(antiDivision(b-1, c, d));
		System.out.println(antiDivision(b, c, d) - antiDivision(a-1, c, d));
	}

	static long antiDivision(long n, int c, int d){
		return n - (division(n, c) + division(n, d) - division(n, LCM.lcm(c, d)));
	}

	static long division(long n, long d){
		return n / d;
	}
}