#include<bits/stdc++.h>
using namespace std;
#define N 100050

vector <int> lda[N];
int m[N], v[N], n, t, s[N], k, max1;
bool cmp(int a, int b)
{
	if (a > b) return 1;
	else return 0;
}
void dfs(int nod)
{
	m[nod] = 1;
	int i;
	for (i = 0; i < v[nod]; i++) dfs(lda[nod][i]);
}
int tmin(int nod)
{
	int i, s[N], max1 = 0;
	if (v[nod] == 0) return 0;
	for(i = 0; i < v[nod]; i++) s[i] = tmin(lda[nod][i]);
	sort(s, s + v[nod], cmp);
	for (i = 0; i < v[nod]; i++) s[i]+= i+1;
	for (i = 0; i < v[nod]; i++) if (max1 < s[i]) max1 = s[i];
	return max1;
}
int main()
{
		int i, x, y, j;
	freopen("zvon.in", "r", stdin);
	freopen("zvon.out", "w", stdout);
	scanf("%d", &t);
	for (j = 0; j < t; j++){
		scanf("%d", &n);
		for(i = 1; i<=n; i++) lda[i].clear();
			for(i = 1; i < n; i++){
			scanf("%d%d", &x, &y);
			lda[x].push_back(y);
			}
		for (i = 1; i <= n; i++)	v[i] = lda[i].size();
		printf("%d\n", tmin(1));
		}
	return 0;
}