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.Generic;
using System.Text;

class AntiDivision
{
    static void Main(string[] args)
    {
        string[] input = Console.ReadLine().Split(' ');
        long A = long.Parse(input[0]);
        long B = long.Parse(input[1]);
        long C = long.Parse(input[2]);
        long D = long.Parse(input[3]);
        long answer = 0;

        for (long i = A; i < B; i++)
        {
            if (i % C != 0 && i % D != 0)
            {
                answer++;
            }
        }

        Console.WriteLine(answer);
    }
}