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.Linq;
using System.Collections;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        //入力
        long[] d = Console.ReadLine().Split().Select(long.Parse).ToArray();
        
        long ans = d[1] - d[0];
        //cで割り切れる数
        long tmp1 = (d[1] - d[0]) / d[2];
        ans -= tmp1;
        //dで割り切れる数
        long tmp2 = (d[1] - d[0]) / d[3];
        ans -= tmp2;
        //cdで割り切れる数
        long tmp3 = (d[1] - d[0]) / (d[2] *d[3]);
        ans += tmp3;

        //出力
        Console.WriteLine(ans);
    }
}