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 extends App {
  val sc = new java.util.Scanner(System.in)
  val l, r = sc.nextLong

  def remainderMinimization2019(min: Long, max: Long): Long = {
    val divisor = 2019
    val startBlock = min / divisor
    val endBlock = max / divisor
    val (i, j) =
      if (startBlock == endBlock) {
        (min, min + 1)
      } else {
        //startBlock < endBlock
        (min, endBlock * divisor)
      }
    ((i % divisor) * (j % divisor)) % divisor
  }

  println(remainderMinimization2019(l, r))
}