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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
    fscanf(STDIN, '%d %d', $left, $right);

    if(floor($left / 2019) != floor($right / 2019)){
        $ans = 0;
    }elseif($right % 2019 == 0){
        $ans = 0;
    }else{
        $mod = $left % 2019;
        $ans = $mod * ($mod + 1);
    }
    echo $ans;