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#include <bits/stdc++.h>
#define debug(x) cout<<#x<<" = "<<x<<"\n"
#define pb push_back
#define ins insert
#define fi first
#define se second
 
using namespace std;
using ull = unsigned long long;
using ll = long long;
using ld = long double;
 
template <typename H, typename T> 
ostream& operator<<(ostream& os, pair<H, T> m){
	return os <<"("<< m.fi<<", "<<m.se<<")";
}
 
template <typename H> 
ostream& operator<<(ostream& os, vector<H> V){
	os<<"{";
	for(int i=0; i<V.size(); i++){
		if(i)os<<" ";
		os<<V[i];
	}
	os<<"}";
	return os;
}
 
void solve();
  
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int t = 1;
	cin>>t;
	while(t--) solve();
	return 0;
}
  
 
bitset<405> zbi[405][2];
bitset<405> ful;

vector<int> graf[405];
 
 
void solve(){
	int n;
	cin>>n;
	ful.reset();
	for(int i = 1; i <= n; i++) ful[i] = 1;
	for(int i = 1; i <= n; i++){
		zbi[i][0].reset(); zbi[i][1].reset();
		graf[i].clear();
	}
	for(int i = 1; i <= n; i++){
		for(int j = 1; j <= n; j++){
			char x;
		   	cin >> x;
		   	if(x == '1') graf[i].pb(j);
		}
	}

	for(int i = 1; i <= n; i++) zbi[i][0][i] = 1;
	int t = 0;
	for(int d = 0; d <= n; d++){
		for(int i = 1; i <= n; i++){
			for(int j = 1; j <= n; j++){
				if((zbi[i][t] | zbi[j][t]) == ful){
					cout<<2*d<<"\n";
					return;
				}
			}
		}
		for(int i = 1; i <= n; i++){
			zbi[i][t^1] = zbi[i][t];
		}
		for(int i = 1; i <= n; i++){
			for(auto x : graf[i]){
				zbi[x][t^1] |= zbi[i][t];
			}
		}
		for(int i = 1; i <= n; i++){
			for(int j = 1; j <= n; j++){
				if((zbi[i][t] | zbi[j][t^1]) == ful){
					cout<<2*d+1<<"\n";
					return;
				}
			}
		}
		t^=1;
	}

 
 
	
 
 
}