import java.io.*;
import java.util.*;
import java.util.stream.*;

public class Main {
    static int[][] matrix;
    static int n;
    static HashMap<Integer, Integer> dp = new HashMap<>();
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        n = sc.nextInt();
        matrix = new int[n][n];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                matrix[i][j] = sc.nextInt();
            }
        }
        System.out.println(dfw((1 << n) - 1));
    }
    
    static int dfw(int m) {
        if (m == 0) {
            return 0;
        }
        if (!dp.containsKey(m)) {
            int ans = 0;
            for (int i = 0; i < n; i++) {
                if ((m & (1 << i)) == 0) {
                    continue;
                }
                for (int j = i + 1; j < n; j++) {
                    if ((m & (1 << j)) == 0) {
                        continue;
                    }
                    ans = Math.max(ans, matrix[i][j] + dfw(m ^ (1 << i) ^ (1 << j)));
                }
                break;
            }
            dp.put(m, ans);
        }
        return dp.get(m);
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}