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: Runtime Error)

<?php
fscanf(STDIN,"%d %d %d %d",$a,$b,$c,$d);

$cnt=0;
for($i=$a;$i<=$b;$i++){
	//$a_0=$i % ($c*$d);
	$a_0=bcpowmod($i, 1, $c*$d);
	if($a_0<>0){
		//$a_1=$i % $c;
		$a_1=bcpowmod($i, 1, $c);
		if($a_1<>0){
			//$a_2=$i % $d;
			$a_2=bcpowmod($i, 1, $d);
			if($a_2<>0){
				$cnt++;
			}
		}
	}
}
echo $cnt;
?>