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;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        long sc = scanner.nextLong() - 1;
        long sc2 = scanner.nextLong();
        long sc3 = scanner.nextLong();
        long sc4 = scanner.nextLong();
        long bet = sc2 - sc + 1;
        
        long tmp = sc2/sc3;
        long tmp2 = sc/sc3;
        long minus1 = tmp - tmp2;

        long tmp3 = sc2/sc4;
        long tmp4 = sc/sc4;
        long minus2 = tmp3 - tmp4;
        
        long tmp5 = sc2/lcm(sc3,sc4);
        long tmp6 = sc/lcm(sc3,sc4);
        long minus3 = tmp5 - tmp6;
        long ans = bet - minus1 - minus2 + minus3;
        System.out.println(ans - 1);
    }
    private static long gcd(long m, long n) {
    if(m < n) return gcd(n, m);
    if(n == 0) return m;
    return gcd(n, m % n);
    }
    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }
}