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;

public class Main {
    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 a1 = (b / c) - ((a - 1) / c);
        long b1 = (b / d) - ((a - 1) / d);
        long lcm = lcm(c, d);
        long lcm1 = (b / lcm) - (a / lcm);
        long ans = a1 + b1 - lcm1;
        System.out.println(b - a - ans +1);
    }

    public static long lcm(long a, long b) {
        return a * b / gcd(a, b);
    }

    public static long gcd(long a, long b) {
        if( b == 0 ) return a;
        return gcd(b, a % b);
    }
}