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

using namespace std;

const int N = 100005;

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

vector<int> g[N];
int dp[N], Subordonati[N];
int TimpMax;

int df(int nod)
{
    vector<int> timp;
    for(int y : g[nod])
        timp.push_back(df(y));
    
    sort(timp.begin(), timp.end());
    reverse(timp.begin(), timp.end());

    int mx = 0;
    for(int i = 0; i < timp.size(); i++)
        mx = max(mx, i + 1 + timp[i]);
    return mx;
}

void sterge(int n)
{
    for(int i = 1; i <= n; i++)
    {
        g[i].clear();
        Subordonati[i] = 0;
        dp[i] = 0;
    }
}

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

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

        fout << df(1) << '\n';
        sterge(n);
    }
    return 0;
}