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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
 
$inputs = explode(' ',trim(fgets(STDIN)));

if($inputs[2] % 2 == 0 && $inputs[3] % 2 == 0){
    $w = $inputs[3] * $inputs[2] / 2;
}else{
    $w = $inputs[3] * $inputs[2];
}

$a = floor($inputs[1] / $inputs[2]);
$b = floor($inputs[1] / $inputs[3]);
if($inputs[0] - 1 == 0){
  $c = 0;
  $d = 0;
  $f = 0;
}else{
  $c = floor(($inputs[0] - 1) / $inputs[2]);
$d = floor(($inputs[0] - 1) / $inputs[3]);
  $e = floor($inputs[1] / $w);
}


$f = floor(($inputs[0] - 1) / $w);

$s = $a + $b - $e - $c - $d + $f;
print $inputs[1] - $inputs[0] + 1 - (int)$s;