[BOJ 1037] 약수

import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.util.Arrays;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(br.readLine());
        StringTokenizer st = new StringTokenizer(br.readLine());
        
        int[] arr = new int[N];
        for(int i=0; i<N; i++) {
            arr[i] = Integer.parseInt(st.nextToken());
        }
        
        Arrays.sort(arr);
        System.out.println(arr[0] * arr[N-1]);
    }
}