#include <fstream>
#include <vector>
#include <algorithm>

#define MAXN 100005

using namespace std;

ifstream f ("zvon.in");
ofstream g ("zvon.out");

int t, n;
int sol[57][MAXN];
vector < int > v[MAXN];

inline int Compare(int x, int y){
    return sol[t][x] > sol[t][y];
}

int DFS(int u){
    for(int i = 0; i < v[u].size(); ++i){
        int nod = v[u][i];
        DFS(nod);
    }
    sort(v[u].begin(), v[u].end(), Compare);
    for(int i = 0; i < v[u].size(); ++i){
        sol[t][u] = max(sol[t][u], sol[t][v[u][i]] + i + 1);
    }

}

int main(){
    f >> t;
    while(t != 0){
        f >> n;
        for(int i = 1; i < n; ++i){
            int x, y;
            f >> x >> y;
            v[x].push_back(y);
        }
        DFS(1);
        if(n != 1) g << sol[t][1] << '\n';
        else g << 0 << '\n';
        for(int i = 1; i <= n; ++i) v[i].clear();
        --t;
    }
}