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 Fortran (gfortran v4.8.4) (judge verdict: Wrong Answer)

program name
    use,intrinsic :: iso_fortran_env
    implicit none
    integer(int64):: l,r,i,j,md

    read*, l,r
    if (r-l+1 >= 2019) then
        print'(i0)', 0
        stop
    end if
    
    if (mod(l,2019) <= mod(r,2019)) then
        print*, mod(l,2019)*(mod(l,2019)+1)
    else
        print*,0
    end if
end program name