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<iostream>
using namespace std;
#include<string>
#include<utility>
#include<algorithm>
#include<vector>
#include<math.h>
#include<bits/stdc++.h>
#include<stdio.h>
 
int main(){
    long long int L,R;
    cin >> L >> R;
    long long int num=(L*(L+1))%2019;
    long long int tmp=0;
       for(int i=L;i<R;++i){
           for(int j=i+1;j<=R;++j){
               tmp=i*j;
               tmp=tmp%2019;
               if(tmp==0){
                   num=0;
                   break;
                   break;
               }
               else{
                   if(tmp<num){
                       num=tmp;
                   }
               }
           }
       }
       cout << num;
}