/* 
	infoarena, Happy Coding 2007
	Zvon
*/

#include <cstdio>
#include <vector>
#include <algorithm>

using namespace std;

const char iname[] = "zvon.in";
const char oname[] = "zvon.out";

#define MAXN  100005

vector <int> G[MAXN], V;

int zvon[MAXN];


bool mycmp(int a, int b) {
	return  a > b;
}

void DF(int n)
{
	vector <int>::iterator it;

	for (it = G[n].begin(); it != G[n].end(); ++ it)
		DF(*it);
	for (it = G[n].begin(); it != G[n].end(); ++ it)
		V.push_back(zvon[*it]);
	sort(V.begin(), V.end(), mycmp);

	for (size_t i = 0; i < V.size(); ++ i)
		if (zvon[n] < V[i] + (i + 1))
			zvon[n] = V[i] + (i + 1);
	vector <int> ().swap(V);
}

int main(void)
{
	freopen(iname, "r", stdin);
	freopen(oname, "w", stdout);

	int T;
	int n;
	int x, y;

	for (scanf("%d", &T); T > 0; -- T) 
	{
		scanf("%d", &n);
		for (int i = 1; i < n; ++ i)
		{
			scanf("%d %d", &x, &y);
			G[x].push_back(y);
		}
		DF(1);
		printf("%d\n", zvon[1]);

		/* Curata */
		memset(zvon, 0, sizeof(zvon));
		for (int i = 1; i <= n; ++ i)
			vector <int> ().swap(G[i]);
	}

	return 0;
}