#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long int ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) { return (ull)rng() % B; }

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<vector<ll>> a(n, vector<ll>(n));
    pair<int, int> p;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            string s;
            cin >> s;
            if (s == "?") {
                p = {i, j};
            } else {
                a[i][j] = stoll(s);
            }
        }
    }
    if (n == 1) {
        cout << 1 << endl;
    } else {
        int k;
        for (int i = 0; i < n; i++) {
            if (a[p.first][i] != 0) k = i;
        }
        ll sum = 0;
        for (int i = 0; i < n; i++) {
            sum += a[i][p.second] * a[i][k];
        }
        cout << -sum / a[p.first][k] << endl;
    }
}