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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int main(){
    int l,r;
    scanf("%d%d",&l,&r);
    int answer=2019;
    r=r-l<2019?r:l+2019;
    for(int i=l;i<=r;i++){
        for(int j=i+1;j<=r;j++){
            int a=i*j%2019;
            answer=a<answer?a:answer;
            if(answer==0) {
                i=r+1;
                j=r+1;
            }
        }
    }
    printf("%d",answer);
}