import java.util.*;

public class Main {
    static int n;
    static int[][] field;
    static int[] dp;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        field = new int[n][n];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                field[i][j] = sc.nextInt();
            }
        }
        dp = new int[1 << n];
        Arrays.fill(dp, -1);
        dp[0] = 0;
        System.out.println(dfw((1 << n) - 1));
    }
    
    static int dfw(int key) {
        if (dp[key] != -1) {
            return dp[key];
        }
        int max = Integer.MIN_VALUE;
        for (int i = 0; i < n - 1; i++) {
            if ((key & (1 << i)) == 0) {
                continue;
            }
            for (int j = i + 1; j < n; j++) {
                if ((key & (1 << j)) == 0) {
                    continue;
                }
                max = Math.max(max, dfw(key ^ ((1 << i) | (1 << j))) + field[i][j]);
            }
            break;
        }
        dp[key] = max;
        return max;
    }
}