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.Scanner;

public class Main {

    public static void main(String[] args) {
        solve();
    }

    private static void solve() {
        Scanner input = new Scanner(System.in);

        long a = Long.parseLong(input.next());
        long b = Long.parseLong(input.next());
        long c = Long.parseLong(input.next());
        long d = Long.parseLong(input.next());

        long ansA1 = (a - 1) / c;
        long ansA2 = (a - 1) / d;
        long ansA3 = (a - 1) / lcm(c, d);

        long ansB1 = b / c;
        long ansB2 = b / d;
        long ansB3 = b / lcm(c, d);

        long ansB = ansB1 + ansB2 - ansB3;
        long ansA = ansA1 + ansA2 - ansA3;

        long ans = ansB - ansA;
        long result = b - (a - 1) - ans;

        System.out.println(result);

    }

    static long lcm (long a, long b) {
    	long temp;
    	long c = a;
    	c *= b;
    	while((temp = a%b)!=0) {
    		a = b;
    		b = temp;
    	}
    	return (c/b);
    }

}