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: Wrong Answer)

fun main(args : Array<String>) {
    val (L, R) = readLine()!!.split(" ").map { it.toLong() }
    val MOD = 2019

    val candidates = mutableListOf<Long>()
    var i = L
    candidates.add(i)
    (0..2019 * 2).forEach {
        i++
        if (i < R) {
            candidates.add(i.mod(2019))
        }
    }

    candidates.sort()
    if (candidates.size == 1) {
        println(0)
    } else {
        println(candidates[0] * candidates[1])
    }
}