#include <iostream>

using namespace std;

int main() {
    int max2_1 = 0, max2_2 = 0, max5_1 = 0, max5_2 = 0, max25_1 = 0, max25_2 = 0, i, a, n, ans1, ans2, ans3 ,ans4, ans5, ans_max;

    cin >> n;
    for (i = 0; i < n; i++){
        cin >> a;
        if (a % 5 != 0 && a % 2 == 0 && a > max2_1){
            max2_2 = max2_1;
            max2_1 = a;
        }
        if (a % 5 != 0 && a % 2 == 0 && a > max2_2 && a <= max2_1)
            max2_2  = a;

        if (a % 5 == 0 && a % 2 != 0 && a > max5_1){
            max5_2 = max5_1;
            max5_1 = a;
        }
        if (a % 5 == 0 && a % 2 != 0 && a > max5_2 && a <= max5_1)
            max5_2  = a;

        if (a % 5 != 0 && a % 2 != 0 && a > max25_1){
            max25_2 = max25_1;
            max25_1 = a;
        }
        if (a % 5 != 0 && a % 2 != 0 && a > max25_2 && a <= max25_1)
            max25_2  = a;
    }

    ans1 = max2_2 * max2_1;
    ans2 = max5_1 * max5_2;
    ans3 = max25_1 * max25_2;
    ans4 = max25_1 * max5_1;
    ans5 = max25_1 * max2_1;

    ans_max = ans1;

    if ( ans2 > ans_max ){
        ans_max = ans2;
    }
    if ( ans3 > ans_max ){
        ans_max = ans3;
    }
    if ( ans3 > ans_max ){
        ans_max = ans3;
    }
    if ( ans3 > ans_max ){
        ans_max = ans3;
    }
    if ( ans3 > ans_max ){
        ans_max = ans3;
    }

    return 0;
}