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 test

integer(8) :: i,j,k,l,r,ll,rr,ans=10**9,new

read(*,*) l,r

ll = mod(l,2019)
rr = mod(r,2019)

if(ll == 0 .or. rr == 0 .or. ll >= rr)then
  ans = 0
else
  do i=ll,rr-1
    do j=i+1,rr
      new = mod(i*j,2019)
      ans = min(new,ans)
    enddo
  enddo
endif

write(*,*) ans

end program