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: Accepted)

program ABC133C
    implicit none
    integer(8)::L,R,ans,i,j
    read*,L,R

    if(R/2019-(L-1)/2019>=1)then
        print'(i0)',0
    else
        ans=2019
        do i=L,R-1
            do j=i+1,R
                ans=min(ans,mod(i*j,2019))
            end do
        end do
        print'(i0)',ans
    end if
end program ABC133C