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.*;
public class Main{
	public static void main(String args[]) {
		Scanner sc=new Scanner(System.in);
		long A=sc.nextLong();
		long B=sc.nextLong();
		int C=sc.nextInt();
		int D=sc.nextInt();
		int a,b,r,gcd,lcm;
		long num,answer;
		sc.close();
		if(C>=D) {
			a=C;
			b=D;
		}else {
			a=D;
			b=C;
		}
		gcd=a/b;
		r=a%b;
		while(a%b!=0) {
			gcd=a/b;
			r=a%b;
			a=b;
			b=r;
		}
		lcm=C*D/gcd;
		num=(B-A+1)/C+(B-A+1)/D-(B-A+1)/lcm;
		answer=(B-A+1)-num;
		System.out.println(answer);
	}
}