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 Scala (2.11.7) (judge verdict: Wrong Answer)

object Main {
  def main(args: Array[String]): Unit = {
    val sc = new java.util.Scanner(System.in)
    val l, r = sc.nextInt
    sc.close

    val j = 2019 < r match {
      case true => 2020
      case _    => r
    }
    val i = 2019 < l match {
      case true => j + 1
      case _ => {
        if (j > 2019) 2019
        else if (2019 < l && l < j - 1) l + 1
        else l
      }
    }

    val ij = i * j
    println(i, j)
    println((math.floor(ij % 2019)).toInt)
  }
}