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 JavaScript (node.js v5.12) (judge verdict: Accepted)

'use strict'
function main(input) {
    const tmp = input.split(' ');
    const L = parseInt(tmp[0], 10);
    const R = parseInt(tmp[1], 10);

    const modNum = 2019;
    if (R - L + 1 >= modNum) {
        console.log(0);
    } else {
        const Lmod = L % modNum;
        const Rmod = R % modNum;

        let minimum = Infinity;
        for (let i = Lmod; i < Rmod; i++) {
            for (let k = i + 1; k <= Rmod; k++) {
                minimum = Math.min((i * k) % modNum, minimum);

            }
        }
        console.log(minimum);

    }
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));