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: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

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

        int count = 0;
        for (int i = A; i <= B; i++)
        {
            if(C == 0)
            {
                count += (i % D == 0) ? 0 : 1;
            }
            else if(D == 0)
            {
                count += (i % C == 0) ? 0 : 1;
            }
            else
            {
                count += (i % C == 0 || i % D == 0) ? 0 : 1;
            }
        }
        Console.WriteLine(count);
    }
}