#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES

#include <bits/stdc++.h>
using namespace std;
using i32 = int; using i64 = long long int; using f64 = double; using str = string;
template <typename T> using vec = vector<T>;
template <typename T> using heap = priority_queue<T>;
void in() {}; template <typename T, typename...TS> void in(T &&x, TS &&...xs) { cin >> x; in(move(xs)...); };
template <typename T> void _out(char *sep, char *end, T &&x) { cout << x << end; };
template <typename T, typename...TS> void _out(char *sep, char *end, T &&x, TS &&...xs) { cout << x << sep; _out(sep, end, move(xs)...); }
#define indef(t, ...) t __VA_ARGS__; in(__VA_ARGS__)
#define get(t) []{ t _; cin >> _; return _; }()
#define put(...) _out("", "", __VA_ARGS__)
#define out(...) _out(" ", "\n", __VA_ARGS__)
#define times(n, i) for (i32 i =  0 ; i <  (n); ++i)
#define range(a, b, i) for (i32 i = (a); i <  (b); ++i)
#define upto(a, b, i) for (i32 i = (a); i <= (b); ++i)
#define downto(a, b, i) for (i32 i = (a); i >= (b); --i)
#define all(xs) (xs).begin(), (xs).end()
#define sortall(xs) sort(all(xs))
#define reverseall(xs) reverse(all(xs))
#define even(x) (((x) & 1) == 0)
#define odd(x) (((x) & 1) == 1)
#define append emplace_back
#define findge lower_bound
#define findgt upper_bound
const i64 MOD = 1000000007;
const f64 EPS = 1e-10;

using u32 = unsigned int;

i32 n;
i64 f[24][24];
i32 dp[16777216];

bool bit(u32 x, i32 i) { return ((x >> i) & 1) > 0; }

i64 dfs(u32 b, i32 i) {
	if (i == n - 1) return 0;
	i64 ret = 0;
	if (dp[~b] > 0) {
		return dp[~b];
	}
	if (bit(b, i)) {
		ret = dfs(b, i + 1);
	}
	else {
		range(i + 1, n, j) {
			if (bit(b, j)) continue;
			ret = max(ret, dfs(b + (1 << j), i + 1) + f[i][j]);
		}
	}
	dp[~b] = ret;
	return ret;
}

i32 main()
{
	in(n);
	times(n, i) {
		times(n, j) {
			f[i][j] = get(i64);
		}
	}

	out(dfs(0, 0));
	return 0;
}