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

using namespace std;

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

int t, n;
int poz[100001];
vector < int > v[100001];
queue < int > coada;

bool cmp(int a, int b)
{
    if (v[a].size() > v[b].size())
        return true;
    return false;
}

void dfs(int nod, int timp, int &timpMax)
{
    timpMax = max(timpMax, timp);
    for (int i=0; i<v[nod].size(); i++)
        dfs(v[nod][i], timp+i+1, timpMax);
}

int main()
{
    f >> t;
    while (t--)
    {
        f >> n;
        for (int i=1; i<n; i++)
        {
            int x, y; f >> x >> y;
            v[x].push_back(y);
        }

        for (int i=1; i<=n; i++)
            sort(v[i].begin(), v[i].end(), cmp);

        int timp = 0;
        dfs(1, 0, timp);
        g << timp << "\n";

        for (int i=1; i<=n; i++)
        {
            v[i].clear();
            poz[i] = 0;
        }
    }
    return 0;
}