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 Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {
    val pw = java.io.PrintWriter(System.out)
    Problem.solve(java.util.Scanner(System.`in`), pw)
    pw.flush()
}

object Problem {
    fun solve(sc: java.util.Scanner, pw: java.io.PrintWriter) {
        val L = sc.next().toLong()
        val R = sc.next().toLong()
        var ans = 2020L
        for (l in (L until R)) {
            for (r in (l + 1)..R) {
                val a = ((l % 2019) * r) % 2019
                if (a == 0L) {
                    pw.println("0")
                    return
                }
                if (ans > a) {
                    ans = a
                }
            }
        }
        pw.println(ans)
    }
}