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: Accepted)

using System;

namespace abc133_c
{
    class Program
    {
        static void Main(string[] args)
        {
            var items = Console.ReadLine().Split(' ');
            var l = long.Parse(items[0]);
            var r = long.Parse(items[1]);

            var min = 2018L;
            for (long i = l; i <= r; i++)
            {
                for (long j = i + 1; j <= r; j++)
                {
                    min = Math.Min(min, (i * j) % 2019L);
                    if (min <= 0)
                    {
                        break;
                    }
                }
                if (min <= 0)
                {
                    break;
                }
            }

            Console.WriteLine($"{min}");
        }
    }
}