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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Linq;
using System.Collections.Generic;

namespace agc030_a
{
    class Program
    {
        static void Main(string[] args)
        {
            var text = Console.ReadLine();
            var list = text.Split(' ').Select(x => int.Parse(x)).ToList();

            var l = list[0];
            var r = list[1];

            var limit = r;
            // limit = Math.Min(limit, r);

            var minmod = int.MaxValue;
            for (int i = l; i <= limit; i++){
                for(int j = l; j <= limit; j++){

                    if (i == j){
                        continue;
                    }

                    var test = (i * j) % 2019;
                    if (test < minmod){
                        minmod = test;
                        if (minmod == 0){
                            break;
                        }
                    }

                }
            }
            
            Console.WriteLine(minmod);
        }
    }
}