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;

namespace ConsoleApp6
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] NL = Console.ReadLine().Split(' ');
            ulong A = ulong.Parse(NL[0]);
            ulong B = ulong.Parse(NL[1]);

            ulong C = ulong.Parse(NL[2]);
            ulong D = ulong.Parse(NL[3]);

            ulong NOC = B / C - (A-1) / C;
            ulong NOD = B / D - (A-1) / D;
            ulong NOCD = B / (C * D) - (A-1) / (C * D);

            Console.WriteLine((B - A + 1) - NOC - NOD + NOCD);

        }

    }
}