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: Time Limit Exceeded)

package main

import (
  "fmt"
  "os"
  "bufio"
  "strconv"
  "math"
)

func main() {
  sc := bufio.NewScanner(os.Stdin)
  sc.Split(bufio.ScanWords)

  sc.Scan()
  l, _ := strconv.Atoi(sc.Text())
  sc.Scan()
  r, _ := strconv.Atoi(sc.Text())

  min := math.MaxInt32
  for i := l; i < r; i++ {
      for j := l + 1; j <= r; j++ {
      tmp := ((i % 2019) * (j % 2019)) % 2019
      if tmp < min {
        min = tmp
      }
    }
    if min == 0 {
      break
    }
  }
  fmt.Println(min)
}