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 %d %d %d', $start, $end, $div1, $div2);

	$ans = $end - $start + 1;
	$ans -= (int)($end / $div1);
	$ans -= (int)($end / $div2);
	$ans += (int)($start / $div1);
	$ans += (int)($start / $div2);
	$ans -= (int)($end / ($div1 * $div2));
	$ans += (int)($start / ($div1 * $div2));

	echo $ans;