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)

def solve
  if (R - L) > 2019
    p 0
    return
  end

  mods = []
  L.upto(R).each do |i|
    mod = i % 2019
    mods << mod
  end

  # p [L, R]
  # p mods

  mods.sort!
  # p mods[0]
  # p mods[1]

  p mods[0] * mods[1]
end

solve