#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream in("zvon.in");
ofstream out("zvon.out");
vector<int> angajati[100001];
int rez(int x)
{
	int i,maxim=0;
	vector<int> timpi;
	for (i = 0; i < angajati[x].size(); i++)
	{
		timpi.push_back(rez(angajati[x][i]));
	}
	sort(timpi.begin(), timpi.end());
	for (i = 0; i < timpi.size(); i++)
	{
		maxim = max(maxim, timpi[timpi.size() - 1 - i] + i+1);
	}
	return maxim;
}
void rez()
{
	int i, n,x,y;
	in >> n;
	for (i = 1; i <= n; i++)
	{
		angajati[i].clear();
	}
	for (i = 1; i < n; i++)
	{
		in >> x;
		in >> y;
		angajati[x].push_back(y);
	}
	out << rez(1)<<"\n";
}
int main()
{
	int i, t;
	in >> t;
	for (i = 1; i <= t; i++)
	{
		rez();
	}
}