#include <bits/stdc++.h>

using namespace std;

long double hasElement(int array[], int size)
{

    int l = 0;
    int r = size - 1;
    sort(array, array + size);
    while (l < r)
    {
        if (array[l] + array[r] == 2020)
        {
            return array[l] * array[r];
        }
        else if (array[l] + array[r] < 2020)
        {
            l++;
        }
        else if (array[l] + array[r] > 2020)
        {
            r--;
        }
    }
    return 0;
}

int main()
{
    int A[] = {1721,
               979,
               366,
               299,
               675,
               1456};
    int arr_size = sizeof(A) / sizeof(A[0]);

    // Function calling
    cout << hasElement(A, arr_size) << endl;
}