import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

class Main {
	public static void main(String[] args) {
		new Main().run();
	}

	void run() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[][] f = new int[n][n];
		for (int i = 0; i < n; ++i) {
			for (int j = 0; j < n; ++j) {
				f[i][j] = sc.nextInt();
			}
		}

		int[] g = new int[1 << n];
		Arrays.fill(g, -Integer.MAX_VALUE / 16);
		g[0] = 0;
		for (int s = 0; s < (1 << n); ++s) {
			if (g[s] < 0)
				continue;
			int o = Integer.numberOfTrailingZeros(~s);
			for (int i = o + 1; i < n; ++i) {
				if (((1L << i) & s) > 0) {
					continue;
				}
				int ne = s | (1 << i) | (1 << o);
				g[ne] = Math.max(g[ne], g[s] + f[i][o]);
			}
		}

		System.out.println(g[(1 << n) - 1]);
	}

	static void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}

}