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

fscanf(STDIN, "%d", $n);
$task = [];
for($i=0;$i<$n;$i++){
    fscanf(STDIN, "%d %d", $a, $b);
    @$task[$b] = (int)($task[$b] + $a);
}
ksort($task);
$now = 0;
foreach ($task as $limit => $time){
    $now += $time;
    if($time > $limit){
        echo "No";
        exit;
    }

}
echo "Yes";