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

using namespace std;

struct Node
{
    int time;
    list<int> sons;
};

using Tree = vector<Node>;

void Dfs(Tree &t, int node)
{
    if (t[node].sons.size() == 0) {
        t[node].time = 0;
        return;
    }

    vector<int> son_times(t[node].sons.size());
    int sons_visited = 0;

    for (int son : t[node].sons) {
        Dfs(t, son);
        son_times[sons_visited++] = t[son].time;
    }
    sort(son_times.begin(), son_times.end(), greater<int>());

    t[node].time = 0;
    for (unsigned i = 0; i < t[node].sons.size(); ++i) {
        t[node].time = max(t[node].time, (int)(son_times[i] + i + 1));
    }
}

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

    int t;
    fin >> t;
    while (t--) {
        int n;
        fin >> n;

        Tree tree(n);
        for (int i = 1; i < n; ++i) {
            int x, y;
            fin >> x >> y;
            tree[x - 1].sons.push_back(y - 1);
        }

        Dfs(tree, 0);
        fout << tree[0].time << "\n";
    }

    return 0;
}