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) {
        Scanner scanner = new Scanner(System.in);
        long a = scanner.nextLong();
        long b = scanner.nextLong();
        long c = scanner.nextLong();
        long d = scanner.nextLong();
        long all = b - a + 1;
        long canDivC=b/ c - a/ c ;
        long canDivD=b/ d - a/ d ;
        long canDivCD= b/ lcm(c,d) - a/ lcm(c,d);
        if (a % c == 0) {
            canDivC++;
        }
        if (a % d == 0) {
            canDivD++;
        }
        if (a % (c * d) == 0) {
            canDivCD++;
        }
        System.out.println(all - canDivC - canDivD + canDivCD);
    }

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

        }
}