#include<iostream>
#include<vector>
using namespace std;
#define ll long long
#define ull unsigned long long
 
vector<vector<int>> G[50001];
bool P[50001];
int res,start;
 
void DFS(int u,int path){
	P[u]=1;
 
	for(vector<int>vt:G[u]){
		if(!P[vt[0]])
			DFS(vt[0],path+vt[1]);
	}
 
	if(path>res){
		res=path;
		start=u;
	}
}
 
void clearp(int n){
	for(int i=1;i<=n;i++)
		P[i]=0;
}
 
void exec(){
	int n,u,v,l;
	cin>>n;
 
	clearp(n);
	for(int i=1;i<=n;i++) G[i].clear();
 
	for(int i=1;i<n;i++){
		cin>>u>>v>>l;
		G[u].push_back({v,l});
		G[v].push_back({u,l});
	}
 
	res=-1e9,start=1;
	DFS(1,0);
 
	clearp(n);
 
	DFS(start,0);
 
	cout<<res<<endl;
}
 
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	int t;
	cin>>t;
 
	while(t--)
	exec();
 
	return 0;
}
 

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