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#include <iostream>
#include <vector>
#include <unordered_map>
using namespace std;

int get_min_dist_index(vector<int> dists, vector<bool> visited) {
    int min_index, min = 400;
    for (int v = 0; v < visited.size(); v++) {
        if (dists[v] <= min && visited[v] == false) {
            min = dists[v];
            min_index = v;
        }
    }
    return min_index;
}

int get_max(vector<int> v) {
    int max = -1;
    for (int e : v) {
        if (e > max)
            max = e;
    }
    return max;
}

int get_min_fuel_size(vector<string> graph, int n) {
    int min_fuel_size = 400;
    for (int src = 0; src < n; src++) {
        vector<int> dists(n);
        vector<bool> visited(n);
        for (int i = 0; i < n; i++) {
            dists[i] = 400;
            visited[i] = false;
        }
        dists[src] = 0;
        for (int c = 0; c < n - 1; c++) {
            int u = get_min_dist_index(dists, visited);
            visited[u] = true;
            for (int v = 0; v < n; v++) {
                if (dists[u] != 400 && !visited[v] && graph[u][v] != '0') {
                    if ((graph[u][v] == '1' || graph[u][v] == '3') && dists[u] + 1 < dists[v]) {
                        dists[v] = dists[u] + 1;
                    } else if (graph[u][v] == '2' && dists[u] < dists[v]) {
                        dists[v] = dists[u];
                    }
                }
            }
        }
        
        // printing solution
        // for (int k = 0; k < n; k++) {
        //     cout << dists[k] << "\n";
        // }
        // cout << "\n";
        if (min_fuel_size > get_max(dists))
        min_fuel_size = get_max(dists);
    }
    return min_fuel_size;
}

int main() {
    int t, n, min_fuel_size;
    cin >> t;
    while (t--) {
        cin >> n;
        vector<string> v(n);
        for (int i = 0; i < n; i++) {
            cin >> v[i];
        }
        min_fuel_size = 400;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                if (v[i][j] == '1') {
                    v[i][j] = '2';
                    v[j][i] = '2';
                    int current_min_fuel_size = get_min_fuel_size(v, n);
                    if (current_min_fuel_size < min_fuel_size)
                        min_fuel_size = current_min_fuel_size;
                    v[i][j] = '3';
                    v[j][i] = '3';
                }
            }
        }
        cout << min_fuel_size << "\n";
    }
}