1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
//
#ifndef __SIZEOF_INT128__
  #define __SIZEOF_INT128__
#endif
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace chrono;
using namespace __gnu_pbds;
template <typename T> using oset =  tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define rep(i, p, k) for(int i(p); i < (k); ++i)
#define per(i, p, k) for(int i(p); i > (k); --i)
#define sz(x) (int)(x).size()
#define sc static_cast
typedef long long ll;
typedef long double ld;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef __int128_t lll;
//#define int ll
template <typename T = int> using par = std::pair <T, T>;
#define fi first
#define se second
#define test int _number_of_tests(in()); while(_number_of_tests--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define pb emplace_back
struct Timer {
    string name{""};
    time_point<high_resolution_clock> end, start{high_resolution_clock::now()};
    duration<float, std::milli> dur;
    Timer() = default;
    Timer(string nm): name(nm) {}
    ~Timer() {
        end = high_resolution_clock::now(); dur= end - start;
        cout << "@" << name << "> " << dur.count() << " ms" << '\n';
    }
};
template <typename T = int> inline T in()
{
    static T x;
    std::cin >> x;
    return x;
}
std::string yn(bool b)
{
    if(b) return "YES\n";
    else return "NO\n";
}
template <typename F, typename S> std::ostream& operator<<(std::ostream& out, const std::pair <F, S>& par);
template <typename T> std::ostream& operator<< (std::ostream& out, const std::vector <T>& wek)
{
    for(const auto& i : wek)out << i << ' ';
    return out;
}
template <typename F, typename S> std::ostream& operator<<(std::ostream& out, const std::pair <F, S>& par)
{
    out << '{'<<par.first<<", "<<par.second<<"}";
    return out;
}
#define show(x) cerr << #x << " = " << x << '\n';
constexpr int maxn = 403;
bool ar[maxn][maxn];
char ka[maxn][maxn];
int od[maxn][maxn];
int n;
bool da(int r){
    // cerr << "da(" << r << ")\n";
    rep(i, 0, n)rep(j, i, n)ka[i][j] = 2;
    rep(w, 0, n){
        // rep(i, 0, n){
            // rep(j, 0, n)cerr << char(j < i ? ' ' : '0'+ka[i][j]);
            // cerr << '\n';
        // }
        vector <int> z;
        rep(i, 0, n)if(od[w][i] > r)z.pb(i);
        if(!z.empty()){
            // cerr << w << ": " << z << '\n';
            rep(b, 0, n){
                int m(0);
                for(auto i: z)m = max(m, od[b][i]);
                rep(a, 0, b+1)if(ka[a][b] && od[a][w] + m > r)--ka[a][b];
                rep(a, b, n)if(ka[b][a] && od[a][w] + m > r)--ka[b][a];
            }
        }
        rep(a, 0, n)rep(b, a, n)if(ka[a][b] == 1)ka[a][b] = 2;
    }
    bool b(0);
    rep(i, 0, n)rep(j, i, n)b |= ka[i][j];
    return b;
}
std::int32_t main()
{
    std::cout.tie(nullptr); //for luck
    std::cin.tie(nullptr); std::ios_base::sync_with_stdio(0);
    test{
        cin >> n;
        rep(i, 0, n)rep(j, 0, n)ar[i][j] = in<char>() == '1';
        rep(i, 0, n)rep(j, 0, n){
            if(i == j)od[i][j] = 0;
            else if(ar[i][j])od[i][j] = 1;
            else od[i][j] = 1e9;
        }
        rep(i, 0, n)rep(a, 0, n)rep(b, 0, n) od[a][b] = min(od[a][b], od[a][i] + od[b][i]);
        int p(0), k(n+1), s;
        while(k > p){
            s = (p+k)/2;
            if(da(s))k = s;
            else p = s+1;
        }
        cout << p << '\n';
    }    
    return 0;
}