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: Accepted)

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

$r = 2018;
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";