#if 1
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <queue>
#include <stack>
#include <array>
#include <deque>
#include <algorithm>
#include <utility>
#include <cstdint>
#include <functional>
#include <iomanip>
#include <numeric>
#include <assert.h>

auto& in = std::cin;
auto& out = std::cout;

int32_t N;
int32_t map[25][25];

int32_t dp[1 << 24];
int32_t func(uint32_t bit)
{
	if (bit == 0) { return 0; }
	auto& memo = dp[bit];
	if (memo) { return memo; }

	int i=0;
	for (; i<N;++i)
	{
		if (bit&(1 << i)) {
			break;
		}
	}
	bit &= ~(1 << i);

	for (size_t j = 0; j < N; j++)
	{
		if (bit & (1<<j)) {
			memo = std::max(memo, func(bit&~(1 << j))+map[i][j]);
		}
	}
	return memo;
}

int main()
{
	using std::endl;
	in.sync_with_stdio(false);
	out.sync_with_stdio(false);

	in >> N;
	for (size_t i = 0; i < N; i++)
		for (size_t j = 0; j < N; j++)
	{
			in >> map[i][j];
	}
	std::cout << func((1 << N) - 1) << endl;

	return 0;
}
#endif