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: Time Limit Exceeded)

using System;
class p
{
  static void Main()
  {
    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]);
    
    int count = 0;
    for (long i = A; i <= B; i++) {
      if ((i % C != 0) && (i % D != 0)) {
        count++;
      }
    }
    Console.WriteLine(count);
  }
}