import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

public long largestValue(int[] A) {
        // Return the largest value of any of A's nonempty subarrays.
            
        long val = 0l;
        long val1[] = new long[3];
        
        if(A.length > 2){      
                        
            for(int i = 0; i < A.length; i++){
            
                for(int j = i; j < A.length; j++){
            
                    val1[0] = val1[0] + (A[i]+A[j]);
                }
            }
            
            val1[1] = largestValue(Arrays.copyOfRange(A, 0, (A.length - 2)));
            
            val1[2] = largestValue(Arrays.copyOfRange(A, 1, (A.length - 1)));
                
            Arrays.sort(val1);
            
            val = val1[2];
            
        }else if(A.length == 2){
        
            val = (A[0] * A[1]);
        } 
        
        return val;
    }

    public static void main(String[] args) {
        
        Solution s = new Solution();
        
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] A = new int[n];
        for(int A_i = 0; A_i < n; A_i++){
            A[A_i] = in.nextInt();
        }
        long result = s.largestValue(A);
        System.out.println(result);
        in.close();
    }
}