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 Go (1.6) (judge verdict: Accepted)

package main

import "fmt"

func main() {
	var l, r int32

	fmt.Scan(&l)
	fmt.Scan(&r)

	if r >= l + 2019 {
		r = l + 2019
	}

	answer := int64(2018)
	for i := l; i < r; i++ {
		for j := i + 1; j <= r; j++ {
			rem := (int64(i) * int64(j)) % 2019
			if rem < answer {
				answer = rem
			}
		}
	}
	fmt.Println(answer)
}