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: Time Limit Exceeded)

<?php
$arr = explode(' ', fgets(STDIN));
$a = (int)$arr[0];
$b = (int)$arr[1];
$c = (int)$arr[2];
$d = (int)$arr[3];

$ans = 0;
for ($i = $a;$i <= $b;$i++) {
    if ($i % $c !== 0 && $i % $d !== 0) {
        $ans++;
    }
}
echo $ans . PHP_EOL;