#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

int dp[1 << 24];

int main() {
  int N;
  cin >> N;
  int V[N][N];

  for (int i = 0; i < N; ++i) {
    for (int j = 0; j < N; ++j) {
      cin >> V[i][j];
    }
  }

  int L = 1 << N;
  memset(dp, 0, sizeof(dp));
  int ans = 0;

  for (int i = 0; i < N / 2; ++i) {
    for (int mask = 0; mask < L; ++mask) {
      if (__builtin_popcount(mask) != 2 * i) continue;

      for (int j = 0; j < N; ++j) {
        if (mask >> j & 1) continue;
        for (int k = j + 1; k < N; ++k) {
          if (mask >> k & 1) continue;
          int nmask = mask | (1 << j) | (1 << k);
          dp[nmask] = max(dp[nmask], dp[mask] + V[j][k]);
          ans = max(ans, dp[nmask]);
        }
        break;
      }
    }
  }

  cout << ans << endl;

  return 0;
}