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.util.*
fun main(args: Array<String>){
	val cin = Scanner(System.`in`)
    val l = cin.nextInt()
    val r = cin.nextInt()

    val l_a = l / 2019
    val l_b = l % 2019
    val r_a = r / 2019
    val r_b = r % 2019

    if (l_a != r_a) {
        println(0)
    } else {
        var ans = 2018
        for (i in l_b..r_b-1) {
            for (j in i+1..r_b) {
                if (ans > (i*j)%2019) {
                    ans = (i*j)%2019
                }
            }
        }
        println(ans)
    }
}