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)

var l,r,min,re,t:int64;
    i,j:longint;
begin
	readln(l,r);
    if r - l + 1 < 2019 then
      begin
        min:=2018; re:=0;
        for i:= l to r - 1 do
          for j:= i + 1 to r do
            begin
              re:= ((i mod 2019) * (j mod 2019)) mod 2019;
              if re < min then min:=re;
            end;  
        t:=r div 2019;
        if (t * 2019 >= l) and (t * 2019 <= r) then min:=0;
      end
    else min:=0;
    write(min);
end.