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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using static MyIO;


public class C
{
	public static void Main()
	{
		long A = GetLong();
		long B = GetLong();
		long C = GetLong();
		long D = GetLong();

		long multiC = Math.Max(0, B/C - (A + C - 1)/C + 1);
		long multiD = Math.Max(0, B/D - (A + D - 1)/D + 1);
		long lcmCD = lcm(C, D);
		long multiCD = Math.Max(0, B/lcmCD - (A + lcmCD - 1)/lcmCD + 1);
		Console.WriteLine($"{multiC} {multiD} {multiCD}");
		Console.WriteLine(B - A + 1 - multiC - multiD + multiCD);
	}

	private static long gcd(long x, long y)
	{
		return (y == 0) ? x : gcd(y, x % y);
	}

	private static long lcm(long x, long y)
	{
		return (x / gcd(x, y)) * y;
	}
}


public static class MyIO
{
	private static string[] args = null;
	private static int num = -1;
	private static int used = -1;

	private static string getArg()
	{
		if(used == num)
		{
			args = Console.ReadLine().Split(' ');
			num = args.Length;
			used = 0;
		}
		return args[used++];
	}

	public static int GetInt(){ return int.Parse(getArg()); }
	public static long GetLong(){ return long.Parse(getArg()); }
	public static double GetDouble(){ return double.Parse(getArg()); }
	public static string GetString(){ return getArg(); }
}