#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for(int (i)=(a); (i)<(n); (i)++)
#define repq(i,a,n) for(int (i)=(a); (i)<=(n); (i)++)
#define repr(i,a,n) for(int (i)=(a); (i)>=(n); (i)--)
#define int long long
template<typename T> void chmax(T &a, T b) {a = max(a, b);}
template<typename T> void chmin(T &a, T b) {a = min(a, b);}
template<typename T> void chadd(T &a, T b) {a = a + b;}
typedef pair<int, int> pii;
typedef long long ll;
constexpr ll INF = 1001001001001001LL;
constexpr ll MOD = 1000000007LL;

int N, board[25][25];
int memo[1<<24];

void solve(int S) {
    rep(i,0,N) {
        if(S >> i & 1) continue;
        rep(j,i+1,N) {
            if(S >> j & 1) continue;
            int nbit = S | (1<<i) | (1<<j);
            int ncost = memo[S] + board[i][j];
            if(ncost > memo[nbit]) {
                memo[nbit] = ncost;
                solve(nbit);
            }
        }
        break;
    }
}

signed main() {
    cin >> N;
    rep(i,0,N) rep(j,0,N) cin >> board[i][j];
    solve(0);
    cout << memo[(1<<N)-1] << endl;
    return 0;
}