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#include<bits/stdc++.h>
#define LL long long
#define LLL __int128
#define uint unsigned
#define ldb long double
#define uLL unsigned long long
using namespace std;
const int N=405,INF=1e8;
int n;
int G[N][N];
inline void MAIN(){
	cin>>n;
	for(int i=1;i<=n;++i){
		for(int j=1;j<=n;++j){
			char c;cin>>c;
			if(i==j)G[i][j]=0;
			else if(c=='1')G[i][j]=1;
			else G[i][j]=INF;
		}
	}
	for(int k=1;k<=n;++k)
		for(int i=1;i<=n;++i)
			for(int j=1;j<=n;++j)
				G[i][j]=min(G[i][j],G[i][k]+G[k][j]);
	int ans=INF;
	for(int u=1;u<=n;++u)
		for(int v=u+1;v<=n;++v){
			int cur=0;
			for(int s=1;s<=n&&cur<ans;++s)
				for(int t=s+1;t<=n&&cur<ans;++t)
					cur=max(cur,min(G[s][t],min(G[s][u]+G[v][t],G[s][v]+G[u][t])));
			ans=min(ans,cur);
		}
	cout<<ans<<'\n';
}
signed main(){
    cin.tie(0)->sync_with_stdio(0);
	int t=1;cin>>t;while(t--)MAIN();
	return 0;
}
/*
*/