#include<bits/stdc++.h>


typedef long long LL;
typedef unsigned long long ULL;
using namespace std;
typedef  vector<int> vi;
typedef  vector<vi> vii;
typedef  vector<tuple<int,int,int>> vti3;



#define FOR(i,a,b) for(int i=a;i<b;i++)
#define pb push_back
#define ll long long
#define pob pop_back
#define si second
#define fi first
#define mii map<int,int>
#define mp make_pair
#define msi map<string,int>
#define musi unorderd_map<string,int>
#define test_n LL N; cin>>N; while(N--)
#define fastio ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
 #define MAXN 100002

vector<int> adj[MAXN];
int depth[MAXN];
vector<int> vertices[MAXN];
int n;

inline int dfs(int node){

int de=0;
    for(auto u:adj[node]){

            de=max(de,dfs(u)+1);

    }

depth[node]=de;
vertices[de].pb(node);
return de;

}


struct fhash {
    ll operator() (string x) const { return 69; }
};

//===============================//
unordered_map<string,int,fhash> oup;
string gof;
int timer=0;
//================================//

inline void mera_util(int node,int k){
++timer;

gof.pb('0'+timer); int myt=timer;
if(k==0){ gof.pb('0'+myt); return;}

    for(auto u:adj[node]){
        mera_util(u,k-1);
    }

gof.pb('0'+myt);

}

//================================//

inline bool mera(int k){
oup.clear();


vi jog;
FOR(i,k,n){ jog.pb(i);}
random_shuffle(jog.begin(),jog.end());

    for(auto i:jog){
    for(auto u:vertices[i]){ timer=0; gof=""; mera_util(u,k);   oup[gof]++; if(oup[gof]>1){return true;}  }
    }



return false;

}

//================================================//

int main(){
fastio;
srand(unsigned(time(0)));
test_n{
cin>>n;
FOR(i,0,n+1){ adj[i].clear(); vertices[i].clear(); }
int chi,a;
FOR(i,1,n+1){
    cin>>chi;
    FOR(j,0,chi){ cin>>a;  adj[i].pb(a); }

}



dfs(1);
int ansi=-9;

int l=0,r=n-1,mid;

while(l<=r){

mid=(l+r)/2;

if(mera(mid)){ ansi=max(ansi,mid); l=mid+1; }
else{ r=mid-1; }

}

cout<<ansi<<"\n";

}//test_n



return 0;}