import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.NoSuchElementException;

public class Main {
	int N;

	int[][] F;
	int[] dp;

	public int dfs(int S){

		if(S == (1 << N)-1)return 0;

		if(dp[S] != -1)return dp[S];

		int ret = 0;

		for(int i = 0;i < N;i++){
			if((S>>i&1)==1)continue;
			for(int j = i + 1;j < N;j++){
				if((S>>j&1)==1 || i == j)continue;
				ret = Math.max(ret,dfs(S | 1 << i | 1 << j) + F[i][j]);
			}
		}
		return dp[S] = ret;
	}
	public void solve() {
		N = nextInt();
		F = new int[N][N];
		for(int i = 0;i < N;i++){
			for(int j = 0;j < N;j++){
				F[i][j] = nextInt();
			}
		}

		dp = new int[1 << N];
		Arrays.fill(dp,-1);
		out.println(dfs(0));
	}

	public static void main(String[] args) {
		out.flush();
		new Main().solve();
		out.close();
	}

	/* Input */
	private static final InputStream in = System.in;
	private static final PrintWriter out = new PrintWriter(System.out);
	private final byte[] buffer = new byte[2048];
	private int p = 0;
	private int buflen = 0;

	private boolean hasNextByte() {
		if (p < buflen)
			return true;
		p = 0;
		try {
			buflen = in.read(buffer);
		} catch (IOException e) {
			e.printStackTrace();
		}
		if (buflen <= 0)
			return false;
		return true;
	}

	public boolean hasNext() {
		while (hasNextByte() && !isPrint(buffer[p])) {
			p++;
		}
		return hasNextByte();
	}

	private boolean isPrint(int ch) {
		if (ch >= '!' && ch <= '~')
			return true;
		return false;
	}

	private int nextByte() {
		if (!hasNextByte())
			return -1;
		return buffer[p++];
	}

	public String next() {
		if (!hasNext())
			throw new NoSuchElementException();
		StringBuilder sb = new StringBuilder();
		int b = -1;
		while (isPrint((b = nextByte()))) {
			sb.appendCodePoint(b);
		}
		return sb.toString();
	}

	public int nextInt() {
		return Integer.parseInt(next());
	}

	public long nextLong() {
		return Long.parseLong(next());
	}

	public double nextDouble() {
		return Double.parseDouble(next());
	}
}