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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		long l = sc.nextLong();
		long r = sc.nextLong();
		sc.close();
		if(l - r > 2018) {
			System.out.println(0);
			return;
		}
		long lMod = (l + 2019) % 2019;
		long rMod = (r + 2019) % 2019;
		if(rMod < lMod) {
			System.out.println(0);
		}
		else if(rMod == lMod)
			System.out.print((rMod * (rMod + 1)) % 2019);
		else
			System.out.println((lMod * (lMod + 1)) % 2019);


	}
}