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 l2019
  integer :: l,r
  integer :: i,j,m

  read(*,*) l,r
  m=2019
  if(l-r.lt.2019) then
     do i=l,r-1
        do j=l+1,r
           if(mod(i*j,2019).lt.m) then
              m=mod(i*j,2019)
           endif
           enddo
     enddo
  else
     m=0
  endif
     write(*,'(i0)') m


end program l2019