#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
const int nmax = 100005;
ifstream fin ("zvon.in");
ofstream fout ("zvon.out");
int cost[nmax];

inline bool cmp(int x, int y)
{
    return cost[x] > cost[y];
}

void dfs(int dad, vector <int> g[nmax])
{
    int i, son, maxx, c;
    if(g[dad].size()==0)
    {
        cost[dad]=0;
        return;
    }
    for(i=0; i<g[dad].size(); i++)
    {
        son=g[dad][i];
        dfs(son, g);
    }
    sort(g[dad].begin(), g[dad].end(), cmp);
    maxx=0, c=1;
    for(i=0; i<g[dad].size(); i++)
    {
        son=g[dad][i];
        maxx=max(maxx, c+cost[son]);
        c++;
    }
    cost[dad]=maxx;
}

void solve_test()
{
    int n, i, x, y;
    vector <int> g[nmax];
    fin >> n;
    if(n==1)
    {
        fout << 0 << "\n";
        return;
    }
    for(i=1; i<n; i++)
    {
        fin >> x >> y;
        g[x].push_back(y);
    }
    for(i=1; i<=n; i++)
        cost[i]=0;
    dfs(1, g);
    fout << cost[1] << "\n";
}

int main()
{
    ios_base::sync_with_stdio(false);
    int t;
    fin >> t;
    while(t--) solve_test();
    fin.close();
    fout.close();
    return 0;
}