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#include <bits/stdc++.h>
using namespace std;
int n;
vector<string> graph;
vector<vector<int>> g;
vector<vector<int>> dist;

void bfs(int s) {
    queue<int> q;
    q.push(s);
    dist[s][s] = 0;
    
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        
        for (int v : g[u]) {
            if (dist[s][v] == -1) {
                dist[s][v] = dist[s][u] + 1;
                q.push(v);
            }
        }
    }
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    int t;
    cin >> t;
    while (t--) {
        cin >> n;
        graph.resize(n);
        for (int i = 0; i < n; ++i) cin >> graph[i];
        
        g.clear();
        g.resize(n + 1);
        for (int u = 1; u <= n; ++u) {
            for (int v = 1; v <= n; ++v) {
                if (u != v && graph[u - 1][v - 1] == '1') {
                    g[u].push_back(v);
                }
            }
        }
        
        dist.assign(n + 1, vector<int>(n + 1, -1));
        for (int s = 1; s <= n; ++s) bfs(s);
        
        int res = INT_MAX;
        
        for (int a = 1; a <= n; ++a) {
            for (int b = a + 1; b <= n; ++b) {
                int cur = 0;
                for (int u = 1; u <= n; ++u) {
                    for (int v = 1; v <= n; ++v) {
                        int org = dist[u][v];
                        int ab = dist[u][a] + dist[b][v];
                        int ba = dist[u][b] + dist[a][v];
                        int new_d = min(org, min(ab, ba));
                        cur = max(cur, new_d);
                    }
                }
                res = min(res, cur);
            }
        }
        
        cout << res << '\n';
    }
    
    return 0;
}