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 Ruby (2.3.3) (judge verdict: Wrong Answer)

l,r = gets.chomp!.split(" ").map(&:to_i)

min = l % 2019
max = r % 2019

if min >= max
    puts 0
else
    ans = 9999999
    min.upto(max - 1) do |i|
        (i + 1).upto(max) do |j|
            x = (i * j) % 2019
            if x < ans
                ans = x
            end
        end
    end

    puts ans
end