#include <cstdio>
#include <algorithm>
#include <vector>
#define v 100010

using namespace std;

int n,t,d[v];

vector <int> w[v];
vector <int> q[v];

int comp(int a, int b)
{
    return a > b;
}

void rezolvare(int x)
{
	d[x] = 0;
	for (vector <int>::iterator it=w[x].begin(); it!=w[x].end(); ++it)
	{
		rezolvare(*it);
		q[x].push_back(d[*it]);
	}
	sort(q[x].begin(), q[x].end(), comp);
	int i=1;
	for (vector <int>::iterator it=q[x].begin(); it!=q[x].end(); it++, i++)
	{
	    if (*it+i>d[x])
            d[x]=*it+i;
	}
}

int main()
{
	int x,y;

	freopen("zvon.in", "r", stdin);
	freopen("zvon.out", "w", stdout);
    scanf("%d", &t);
	for (int i=1; i<=t; i++)
	{
		scanf("%d", &n);
		for (int i=0; i<v; i++)
		{
            w[i].clear();
            q[i].clear();
		}
		for (int i=1; i<n; i++)
		{
			scanf("%d%d", &x, &y);
			w[x].push_back(y);
		}
		rezolvare(1);
		printf("%d\n", d[1]);
	}

return 0;
}