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;

namespace Atcoder_program_test_Csharp
{
    using System;
    class Program
    {
        static void Main(string[] args)
        {
            string line_one = Console.ReadLine();
            string[] str = line_one.Split(' ');
            long A = int.Parse(str[0]);
            long B = int.Parse(str[1]);
            int C = int.Parse(str[2]);
            int D = int.Parse(str[3]);
            long count = 0;
            long x = A;
            for (; ; )
            {
                if (x % C == 0) { }
                else if (x % D == 0) { }
                else count = count + 1;
                if (x >= B)
                {
                    break;
                }
                else x = x + 1;
            }
            Console.Write(count);
        }
    }
}