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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i<n; i++)
typedef long long ll;
using namespace std;
int INF = 1001001001;

		

int main(){
	ll l,r;
	cin >> l >> r;
	int ans=2020;
	if(r-l >= 2018){
		ans=0; 
	}else{
		for(int i=l; i<=r-1; i++){
			for(int j=i+1; j<=r; j++){
				ans = min(ans, (i*j)%2019);
			}
		}
	}
	cout << ans << endl;

	return 0;
}