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"
	"math"
)

func intMin(x, y int) int {
	return int(math.Min(float64(x), float64(y)))
}

func main() {
	var L, R int
	fmt.Scan(&L, &R)

	if (R - L) >= 2019 {
		fmt.Println(0)
		return
	}

	L, R = L%2019, R%2019
	if L > R {
		fmt.Println(0)
		return
	}

	ans := 2019
	for i := L; i < R; i++ {
		for j := i + 1; j <= R; j++ {
			ans = intMin(ans, (i*j)%2019)
		}
	}
	fmt.Println(ans)
}