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#include <bits/stdc++.h>
using namespace std;

#ifdef DEBUG
#include "debug.hpp"
#else
#define debug(...) (void)0
#endif

namespace R = ranges;
namespace V = views;
auto ra(auto x, auto y) { return R::iota_view(x, y); }
auto rae(auto x, auto y) { return ra(x, y + 1); }
using i64 = int64_t;

const int oo = 1E9 + 7;
const int nax = 400;
int dist[nax][nax];
void solve() {
  int n;
  cin >> n;
  for (auto i : ra(0, n)) {
    for (auto j : ra(0, n)) {
      char c;
      cin >> c;
      if (c == '1') {
        dist[i][j] = 1;
      } else {
        dist[i][j] = oo;
      }
    }
    dist[i][i] = 0;
  }

  for (auto k : ra(0, n)) {
    for (auto i : ra(0, n)) {
      for (auto j : ra(0, n)) {
        dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
      }
    }
  }

  int ans = oo;
  for (auto i : ra(0, n)) {
    for (auto j : ra(i + 1, n)) {
      int local = -oo;
      for (auto k : ra(0, n)) {
        for (auto l : ra(k + 1, n)) {
          local = max(local, min({dist[k][l], dist[i][k] + dist[j][l],
                                  dist[j][k] + dist[i][l]}));
        }
      }
      ans = min(ans, local);
    }
  }
  cout << ans << '\n';
}

int32_t main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int t = 1;
  cin >> t;
  for (auto tc_n : ra(0, t)) {
    debug(tc_n);
    solve();
    cout.flush();
  }
}