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 = Long.parseLong(sc.next());
        long r = Long.parseLong(sc.next());
        long ans = Long.MAX_VALUE;
        long num = 0;
        for (long i = l; i < r; i++) {
            for (long j = i + 1; j <= r; j++) {
                num = (i * j) % 2019;
                if (num < ans) {
                    ans = num;
                }
                if (num == 0) {
                    System.out.println(0);
                    return;
                }
            }
        }
        System.out.println(ans);
    }
}