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)

# スペース区切りの整数の入力
L,R=gets.chomp.split(" ").map(&:to_i);
qL=L/2019
qR=R/2019
if(qL<qR)
 print(0)
else
modL=L.modulo(2019)
modR=R.modulo(2019)
ans=[(modL*(modL+1)).modulo(2019),(modR*(modR-1)).modulo(2019)].min
 print(ans)
end