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.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 c = 0;
		long d = 0;
		long cd = 0;
		
		long koub = 0;
		
		koub = C * D / gcd(C, D);
		
		if(A == B) {
			if(A % C != 0 && A % D != 0) {
				System.out.println(1);
				return;
			} else {
				System.out.println(0);
				return;
			}
		}
		
		if(A % C != 0) {
			c = (B - ((A - A % C) / C + 1) * C) / C + 1;
		} else {
			c = (B - A) / C + 1;
		}
		
		if(A % D != 0) {
			d = (B - ((A - A % D) / D + 1) * D) / D + 1;
		} else {
			d = (B - A) / D + 1;
		}
		
		if(A % koub != 0) {
			cd = (B - ((A - A % koub) / koub + 1) * koub) / koub + 1;
		} else {
			cd = (B - A) / koub + 1;
		}
		
		System.out.println(B - A + 1 - c - d + cd);
	}
	
	public static long gcd(long a, long b) {
		if(b == 0) {
			return a;
		}
		return gcd(b, a % b);
	}
}