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: Accepted)

l, r = gets.split.map &:to_i
l %= 2019 * 2
r %= 2019 * 2
if l > r
  puts 0
  exit 0
end
 
res = 2019
 
 
l.upto(r) do |i| 
    r.downto(l) do|j|
        break if i >= j
        break if res == 0
        res = [res, (i * j) % 2019].min
    end
end
 
puts res