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 (l, r) = readLine()!!.split(" ").map { it.toInt() }
    val a = l % 2019
    val b = r % 2019
    var min = 2019
    if (r - l > 2019) min = 0
    if (a < b) {
        for (i in a until b+1) {
            if (b - a == 1) {
                min = a * b % 2019
                break
            }
            for (j in i + 1 until b+1) {
                val x = i * j
                val modX = x % 2019
                if (min > modX) min = modX
            }
        }
    } else {
        for (i in b until a+1) {
            if (a - b == 1) {
                min = a * b % 2019
                break
            }
            for (j in i + 1 until a+1) {
                val x = i * j
                val modX = x % 2019
                if (min > modX) min = modX
            }
        }
    }
    println(min)
}