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#include <iostream>
#include <cstdint>
#include <unordered_map>
#include <unordered_set>
#include <deque>
#include <utility>
#include <optional>

struct InputData {
    unsigned n;
    std::unordered_map<unsigned, std::unordered_set<unsigned>> graph;
    std::optional<std::pair<unsigned, unsigned>> teleport;
} input_data;

void parse_input() {
    std::cin >> input_data.n;
    for (unsigned i = 0; i < input_data.n; i++) {
        std::string line;
        std::cin >> line;
        for (unsigned j = 0; j < input_data.n; ++j) {
            unsigned connects = line[j] - '0';
            if (connects) input_data.graph[i].insert(j);
        }
    }
}

struct BfsData {
    unsigned point;
    unsigned dist;
};

BfsData bfs_max_dist(const unsigned node) {
    BfsData res{node, 0};
    std::deque<BfsData> q{res};
    std::unordered_set<unsigned> seen;

    while (!q.empty()) {
        BfsData node_data = q.front();
        // std::cerr << "node_data: " << node_data.point << ' ' << node_data.dist << '\n';
        q.pop_front();
        if (seen.contains(node_data.point))
            continue;
        
        if (node_data.dist > res.dist)
            res = node_data;
        
        seen.insert(node_data.point);
        for (const auto elem : input_data.graph[node_data.point]) {
            q.emplace_back(elem, node_data.dist+1);
        }

        if (!input_data.teleport.has_value())
            continue;

        if (node_data.point == input_data.teleport->first) {
            q.emplace_back(input_data.teleport->second, node_data.dist);
        } else if (node_data.point == input_data.teleport->second) {
            q.emplace_back(input_data.teleport->first, node_data.dist);
        }
    }
    return res;
}

unsigned get_diameter() {
    const auto first = bfs_max_dist(0);
    const auto second = bfs_max_dist(first.point);
    return second.dist;
}

unsigned brute_force() {
    std::optional<unsigned> res = std::nullopt;
    for (unsigned i = 0; i < input_data.n-1; ++i) {
        for (unsigned j = i+1; j < input_data.n; ++j) {
            input_data.teleport = {i, j};
            const auto result = get_diameter();
            if (!res.has_value() || result < res.value())
                res = result;
        }
    }
    return res.value_or(2137);
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(NULL);
    unsigned t;
    std::cin >> t;
    for (unsigned i = 0; i < t; ++i) {
        input_data = { 0 };
        parse_input();
        const auto res = brute_force();
        std::cout << res << '\n';
    }

    return 0;
}