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: Wrong Answer)

package main

import(
    "fmt"
)

func main() {
    var l, r int
    fmt.Scan(&l, &r)

    if r - l >= 2019 {
        fmt.Println(0)
        return
    }

    var min int
    min = 2020
    for i:= l;i <= r;i++ {
        for j:= l+1;j <= r; j++ {
            if min > (i*j)%2019 {
                min = (i*j)%2019
            }
        }
    }

    fmt.Println(min)
}