Problem:
Score : 300 points

Problem Statement

You are given two non-negative integers L and R.
We will choose two integers i and j such that L \leq i < j \leq R.
Find the minimum possible value of (i \times j) \mbox{ mod } 2019.

Constraints

All values in input are integers.

0 \leq L < R \leq 2 \times 10^9

Input

Input is given from Standard Input in the following format:

L R

Output

Print the minimum possible value of (i \times j) \mbox{ mod } 2019 when i and j are chosen under the given condition.

Sample Input 1

2020 2040

Sample Output 1

2

When (i, j) = (2020, 2021), (i \times j) \mbox{ mod } 2019 = 2.

Sample Input 2

4 5

Sample Output 2

20

We have only one choice: (i, j) = (4, 5).

Solution in Perl (v5.18.2) (judge verdict: Wrong Answer)

($x, $y) = split(/ /, <>);

$r = 2018;
if($y < 2019){
	$r = $x * ($x + 1);
}else{
	for $i ($x .. $y - 1){
		for $n ($x + 1 .. $y){
			$mod = ($i * $n) % 2019;
			if($mod == 0){
				$r = 0;
				last;
			}
			$r = $mod if($mod < $r);
		}
		last if($r == 0);
	}
}

print "$r\n";