#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 mask = 0; mask < L; ++mask) {
    ans = max(ans, dp[mask]);
    if (__builtin_popcount(mask) & 1) 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]);
      }
      break;
    }
  }

  cout << ans << endl;

  return 0;
}