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#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;

template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define debug(x) cout << "[" <<  #x << " " << x << "] ";

#define ar array
#define ll long long
#define ld long double
#define sz(x) ((int)x.size())
#define all(a) (a).begin(), (a).end()

typedef vector<int> vi;
typedef pair<int, int> pi;

const int MAX_N = 1e5 + 5;
const ll MOD = 1e9 + 7;
const ll INF = 1e9;
const ld EPS = 1e-9;

int bfs(const vector<unordered_set<int>> &adj, int start, vector<int> &dist) {
    queue<int> q;
    q.push(start);
    dist[start] = 0;
    int farthest_node = start;
    while (!q.empty()) {
        int node = q.front();
        q.pop();
        for (int neighbor : adj[node]) {
            if (dist[neighbor] == -1) {
                dist[neighbor] = dist[node] + 1;
                q.push(neighbor);
                if (dist[neighbor] > dist[farthest_node]) {
                    farthest_node = neighbor;
                }
            }
        }
    }
    return farthest_node;
}

int find_graph_diameter(vector<unordered_set<int>> &adj) {
    int n = adj.size();
    vector<int> dist(n, -1);
    dist[0] = 0;
    int farthest = bfs(adj, 0, dist);
    fill(all(dist), -1);
    bfs(adj, farthest, dist);
    return *max_element(all(dist));
}

unordered_set<int> connect_vertices(vector<unordered_set<int>> &adj, int u, int v) {
    unordered_set<int> new_elements;
    for (int n : adj[v]) {
        if (n != u && adj[u].find(n) == adj[u].end()) {
            new_elements.insert(n);
            adj[u].insert(n);
            adj[n].insert(u);
        }
    }
    return new_elements;
}

void disconnect_vertices(vector<unordered_set<int>> &adj, int u, unordered_set<int> new_elements) {
    for (int n : new_elements) {
        adj[u].erase(n);
        adj[n].erase(u);
    }
}

void print_graph(vector<unordered_set<int>> &adj) {
    for (int i = 0; i < (int)adj.size(); i++) {
        for (int j : adj[i]) {
            cout << i+1 << " " << j+1 << "\n";
        }
    }
}

void solve() {
    int n;
    cin >> n;
    vector<unordered_set<int>> adj(n);
    for (int i = 0; i < n; i++) {
        string s;
        cin >> s;
        for (int j = 0; j < n; j++) {
            if (s[j] == '1') {
                adj[i].insert(j);
            }
        }
    }



    // print_graph(adj);

    int result = INF;
    pair<int, int> best_pair;
    for (int u = 0; u < n; u++) {
        for (int v = u + 1; v < n; v++) {
            unordered_set<int> new_elements = connect_vertices(adj, u, v);
            unordered_set<int> v_neighbours = adj[v];
            for (int n : v_neighbours) {
                adj[n].erase(v);
                adj[v].erase(n);
            }
            // cout << "AFTER CONNECTING " << u+1 << " " << v+1 << "\n";
            // print_graph(adj);
            int diameter = find_graph_diameter(adj);
            if (diameter < result) {
                result = diameter;
                best_pair = {u, v};
            }
            disconnect_vertices(adj, u, new_elements);
            for (int n : v_neighbours) {
                adj[n].insert(v);
                adj[v].insert(n);
            }
            // cout << "AFTER DISCONNECTING " << u+1 << " " << v+1 << "\n";
            // print_graph(adj); //
        }
    }

    cout << result << "\n";
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int tc = 1;
    cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t << ": ";
        solve();
    }
}