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)

import java.io.*
import java.util.*

var pw = PrintWriter(System.out)
const val MOD = 2019
fun solve(L: Int, R: Int){
    var ans = 2019*2019
    val range = when{
        R - L >= 2019 -> IntArray(2019){ it }.toList()
        else -> (L..R).toList().map{ it % 2019 }
    }
    // println(range.toString())
    for (i in 0 until range.size){
        for (j in i+1 until range.size){
            ans = Math.min(ans, (range[i] * range[j]) % 2019)
        }
    }
    println(ans)
    return
}


fun main(args: Array<String>) {
    fun StringArray(size: Int, init: (Int) -> String = { "\u0000" }): Array<String> {
        return Array<String>(size, init)
    }
    class Scanner(stream: InputStream) {
        private val reader = BufferedInputStream(stream).bufferedReader()
        private var st: StringTokenizer? = null
        fun next(): String {
            while (!(st?.hasMoreTokens() ?: false)) st = StringTokenizer(reader.readLine())
            return st!!.nextToken()
        }
    }
    val sc = Scanner(System.`in`)
    val L = sc.next().toInt()
    val R = sc.next().toInt()
    solve(L, R)
}