import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
	
	public static long MOD = 1000000007;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final int n = sc.nextInt();
		
		final int max = 1000;
		int[][] adj = new int[n][n];
		for(int i = 0; i < n; i++){
			for(int j = 0; j < n; j++){
				adj[i][j] = max - sc.nextInt();
			}
		}
		
		int[] DP = new int[1 << n];
		Arrays.fill(DP, Integer.MAX_VALUE / 2 - 1);
		DP[0] = 0;
		
		for(int bit = 0; bit < (1 << n); bit++){
			//System.out.println(bit);
			int i = 0;
			for (; (bit & (1 << i)) != 0; ++i);
			
			final int fst = 1 << i;
			for(int j = i + 1; j < n; j++){
				final int snd = 1 << j;
				
				final int next_bit = bit | fst | snd;
				DP[next_bit] = Math.min(DP[next_bit], DP[bit] + adj[i][j]);
			}
		}
		
		System.out.println(max * (n / 2) - DP[(1 << n) - 1]);
	}
}