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#include <bits/stdc++.h>
#define fi first
#define sc second
#define pb push_back
#define rep(i,p,k) for(int i=(p);i<(k);++i)
#define forn(i,p,k) for(int i=(p);i<=(k);++i)
#define forr(i,k,p) for(int i=(k)-1;i>=(p);--i)
#define each(a,b) for(auto&a:b)
#define all(v)  begin(v), end(v)
#define RET(smth)   return void(cout<<(smth)<<'\n');
#define sz(v) (int)v.size()
using namespace std;
using pii = pair<int,int>;
using ll = long long;
using lll = __int128_t;
using Vi = vector<int>;
#ifdef DEBUG
#include "debug.h"
#else
#define debug(...) ;
#endif

const int inf = 1e9;

struct MAIN {
    void TEST() {
        int n; cin >> n;
        vector<vector<int>> d(n, Vi(n));
        rep(i,0,n) rep(j,0,n) {
            char z; cin >> z;
            d[i][j] = z == '0' ? inf : 1;
        }
        rep(i,0,n) d[i][i] = 0;
        rep(k,0,n) rep(i,0,n) rep(j,0,n) d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
        int r = inf;
        rep(a,0,n) rep(b,a+1,n) {
            int t = 0;
            rep(x,0,n) rep(y,x+1,n) {
                t = max(t, min({d[a][x]+d[b][y], d[a][y]+d[b][x], d[x][y]}));
                if(t >= r) goto A;
            }
            r = t;
            A:;
        }
        cout << r << '\n';
    }
};

int main() {
#ifndef DEBUG
    cin.tie(0) -> sync_with_stdio(0);
#endif
    int Z = 1;
    cin>>Z;
    while(Z--)  MAIN{}.TEST();
    return 0;
}