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)

import scala.io.StdIn._
object Main extends App {
  val Array(l, r) = readLine.split(" ").map(_.toLong)
  val is = l to Math.min(r - 1, l + 2019)
  val js = l + 1 to Math.min(r, l + 2020)

  println(is.foldLeft(Long.MaxValue){(min, i) =>
    js.foldLeft(min){(minmin, j) =>
      Math.min(minmin, j * j % 2019)
    }
  })
}