#include <cstdio>
#include <cassert>
#include <cmath>
#include <cstring>

#include <algorithm>
#include <iostream>
#include <vector>
#include <functional>
#include <utility>
#include <set>
#include <map>
#include <queue>

#include <unordered_map>

#define _rep(_1, _2, _3, _4, name, ...) name
#define rep2(i, n) rep3(i, 0, n)
#define rep3(i, a, b) rep4(i, a, b, 1)
#define rep4(i, a, b, c) for (int i = int(a); i < int(b); i += int(c))
#define rep(...) _rep(__VA_ARGS__, rep4, rep3, rep2, _)(__VA_ARGS__)

using namespace std;
using i16 = short;
using i64 = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using f80 = long double;

const int N_MAX = 24;
unordered_map<int, int> memo;
int cost[N_MAX][N_MAX];

int rec(int state) {
  if (memo.find(state) == memo.end()) {
    int i = __builtin_ctz(state);
    int s = state & (state - 1), t = s;
    int best = 0;
    for (; t; t &= t - 1) {
      int j = __builtin_ctz(t);
      best = max(best, cost[i][j] + rec(s ^ (1 << j)));
    }
    memo[state] = best;
  }
  return memo[state];
}

void solve() {
  int N;
  while (~scanf("%d", &N)) {
    memo.clear();
    memo[0] = 0;
    rep(i, N) rep(j, N) scanf("%d", &cost[i][j]);
    printf("%d\n", rec((1 << N) - 1));
  }
}

int main() {
  clock_t beg = clock();
  solve();
  clock_t end = clock();
  fprintf(stderr, "%.3f sec\n", double(end - beg) / CLOCKS_PER_SEC);
  return 0;
}