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 args[]){
        Scanner sc = new Scanner(System.in);

        long a = sc.nextLong();
        long b = sc.nextLong();
        int c = sc.nextInt();
        int d = sc.nextInt();

        long count = b - a + 1;

        count -= ((b / c) - ((a-1) / c));
        System.out.println(count);
        count -= ((b / d) - ((a-1) / d));
        System.out.println(count);
        count += ((b / lcm(c, d)) - ((a-1) / lcm(c, d)));

        System.out.println(count);
        sc.close();
    }

    static int gcd(int m, int n) {
        if (m < n)
            return gcd(n, m);
        if(n == 0)
            return m;
        return gcd(n, m%n);
    }

    static int lcm(int m, int n){
        return ((m*n) / gcd(m, n));
    }
}