#include<iostream>
#include<fstream>
#include<algorithm>
#include<cstring>
#include<vector>
using namespace std;

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

int n,m,T,solutie;
int w[100004];
vector <int> L[100004];

inline bool cmp(const int a, const int b)
{
   return (w[a] > w[b]);
}

void DFS(int x)
{
    int i, l = L[x].size(), node;
    for (i = 0; i < l; ++ i)
        DFS(L[x][i]);
    sort(L[x].begin(), L[x].end(), cmp);
    for (i = 0; i < l; ++ i)
        w[x] = max(w[x], w[L[x][i]] + i + 1);
}

void Rezolva()
{
   int i;
   DFS(1);
   for (i=1; i<=n; i++)
   L[i].clear();
   
   solutie = w[1];
}

void Afisare()
{
  fout << solutie <<"\n";
}


void Citire()
{
  int i,j,x,y;
  fin >> T;
  for (i=1; i<=T; i++)
  {
     fin >> n;
     for (j=1; j<n; j++)
       {
          fin >> x >> y;
          L[x].push_back(y);
       }
     Rezolva();
     Afisare();
  }
}

int main ()
{
 Citire();
 fin.close();
 fout.close();
 return 0;
}