#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int N,T;
vector<int> V[100100];
int dfs(int v){
	int val,rs=0;
	for(auto it:V[v]){
		val = dfs(it);
		rs = max(rs,val);
	}
	return max(rs,int(V[v].size()))+1; 
}
int main(){
    ifstream cin("zvon.in");
    ofstream cout("zvon.out");
    ios_base::sync_with_stdio(0);
    cin >> T;
    while(T--){
		cin >> N;
		for(int x,y,i=1;i<N;i++){cin >> x >> y; V[x].push_back(y);}
		cout << dfs(1)-1<< '\n';
		for(int i = 0;i<N;i++) V[i].clear();
		//cout << "________\n";
	}
   
	return 0;
}