#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <vector>

using namespace std;

#define pb push_back
#define NMAX 100010
#define MP make_pair
#define sz size()
#define ss second 
#define ff first

int n;
vector<int> list[NMAX];
int niv[NMAX], nr[NMAX];
int _max = 0;

inline int MAX(int a, int b) { return (a > b) ? (a) : (b); }

void read()
{
	scanf("%d", &n);
	for(int i = 1, x, y; i < n; ++i)
	{
		scanf("%d %d\n", &x, &y);
		list[x].pb(y);
	}
}	

int df(int x)
{
	if(!(list[x].sz))
		return 0;
	vector<int> p;
	for(vector<int> :: iterator it = list[x].begin(); it != list[x].end(); ++it)
		p.pb(df(*it));
	sort(p.begin(), p.end());

	int _max = 0;
	for(int t = 1, it = p.sz-1; it >= 0; --it, ++t)
		_max = MAX(_max, p[it] + t); 
	return _max;
}

int main()
{
	freopen("zvon.in", "r", stdin);
	freopen("zvon.out", "w", stdout);

	int nr;
	for(scanf("%d", &nr); nr; --nr)
	{

		read();

		printf("%d\n", df(1));

		memset(niv, 0, sizeof(niv));
		for(int i = 0; i < NMAX; ++i)
			list[i].clear();
		_max = 0;
	}
	return 0;
}