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

using namespace std;

ifstream fin("zvon.in");
ofstream fout("zvon.out");

const int NMax = 100000;

int N, T, DP[NMax + 5];
vector <int> G[NMax + 5];

inline bool compare(int A, int B) { return A > B;}

void DFS(int Nod, int Tata)
{
    vector <int> S;

    for(auto Vecin : G[Nod])
        if(Vecin != Tata)
            DFS(Vecin, Nod), S.push_back(DP[Vecin]);

    sort(S.begin(), S.end(), compare);

    for(int i = 0; i < S.size(); i++)
        DP[Nod] = max(DP[Nod], S[i] + i + 1);
}

int main()
{
    fin >> T;

    while(T--) {
        fin >> N;

        for(int i = 1, a, b; i < N; i++) {
            fin >> a >> b;

            G[a].push_back(b);
            G[b].push_back(a);
        }
        DFS(1, 0); fout << DP[1] << '\n';

        for(int i = 1; i <= N; i++)
            DP[i] = 0, G[i].clear();
    }
    fin.close();
    fout.close();

    return 0;
}