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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

uses math;
var
        l,r,i,j,o,p:longint;
begin
        read(l,r);
        if r-l>2020 then writeln(0) else
        begin
                o:=maxlongint;
                for i:=l to r do
                        for j:=i+1 to r do
                        o:=min(o,i*j mod 2019);
                writeln(o);
        end;
end.