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 (L%2019==0||R%2019==0) {
			System.out.println(0);
			return ;
		}
		if (L/2019!=R/2019) {
			System.out.println(0);
			return ;
		}
		int min = 2019;
		for (long i=L;i<R;i++) {
			for (long j=i+1;j<=R;j++) {
				int temp = (int) (((i%2019)*(j%2019))%2019);
				if (temp<min) {
					min = temp;
				}
			}
		}
		System.out.println(min);
	}
}