#include <bits/stdc++.h>

using namespace std;

typedef array< array<bool, 24>, 24> Matrix;

int n;
int f[24][24];

int solve(int cur, Matrix used) {
	if (cur == n) return 0;
	int res = 0;
	for (int i = 0; i < n; i++) {
		if (i == cur || used[cur][i]) continue;
		Matrix nex(used);
		for (int j = 0; j < n; j++) {
			nex[cur][j] = true;
			nex[j][cur] = true;
			nex[i][j] = true;
			nex[j][i] = true;
		}
		res = max(res, solve(cur + 1, nex) + f[cur][i]);
	}
	if (res == 0) return solve(cur + 1, used);
	return res;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cin >> n;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			cin >> f[i][j];
		}
	}
	Matrix used{};
	cout << solve(0, used) << endl;
	return 0;
}