#include <fstream>
#include <vector>
#include <cstring>
#include <algorithm>
using namespace std;
int t,n,dp[100001];
vector<int> g[100001];
bool cmp(int a,int b)
{
	return dp[a]>dp[b];
}
void dfs(int nod)
{
	size_t i;
	for(i=0;i<g[nod].size();++i)
		dfs(g[nod][i]);
	sort(g[nod].begin(),g[nod].end(),cmp);
	for(i=0;i<g[nod].size();++i)
		dp[nod]=max(dp[nod],(int)i+dp[g[nod][i]]+1);
}
ifstream fin("zvon.in");
ofstream fout("zvon.out");
int main()
{
	int i,x,y;
	fin>>t;
	while(t--)
	{
		fin>>n;
		for(i=1;i<n;++i)
		{
			fin>>x>>y;
			g[x].push_back(y);
		}
		dfs(1);
		fout<<dp[1]<<"\n";
		memset(g,0,sizeof g);
		memset(dp,0,sizeof dp);
	}
	return 0;
}