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 abc133c
  use,intrinsic :: iso_fortran_env
  implicit none
  integer(int64) :: l, r, i, j, ans
  read *, l, r
  if (l - r + 1 >= 2019) then
     print *, 0
  else
     ans = 2019
     do j = l+1,r
        do i = l,j
           ans = min(ans,mod(i*j,2019))
           if (ans == 0) exit
        end do
     end do
     print *, ans
  end if
end program abc133c