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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

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();

		if (R - L >= 2019) {
			System.out.println(0);
			return;
		}

		long ans = Long.MAX_VALUE;
		for (long i = L; i < R; i++) {
			long tmp =0;
			for (long j = i+1; j <= R; j++) {
				tmp=(i*j)%2019;
				ans = Math.min(ans, tmp);
			}
		}
		System.out.println(ans);
	}
}