#include <iostream>
#include <queue>
#include <functional>
#include <map>
using namespace std;

struct edge
{
	int from;
	int to;
	int cost;
	edge(int a, int b, int c){from = a, to = b, cost = c;}
};

int number_vertces;
bool *visited;
int arr[100][100];
int main()
{
	//freopen("inp.txt", "r", stdin);

	map<int, int> abo;

	int e, cc, F,T;
	//cout << "Enter number of v :\n";
	cin >> number_vertces;
	//cout << "Enter number of edges :\n";
	cin >> e;
	for (int i = 0; i < e; i++)
	{
		cin >> F >> T >> cc;
		arr[F][T]  = arr[T][F]= cc;
	}

	visited = new bool[number_vertces];
	vector<edge> MST;
	edge E(0,0,0);
	priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int> > > Q;
	Q.push(make_pair(0, 0));
	visited[0] = true;
	int v, CUR;
	pair<int, int> C;
	int cost = 0;
	for (int i = 0; i < number_vertces; i++)
		visited[i] = false;

	while (!Q.empty())
	{
		C = Q.top();

		Q.pop();
		if (!visited[C.second])
		{
			cost += C.first;
			edge k(C.second, abo[C.second], C.first);
			MST.push_back(k);

		}
		visited[C.second] = true;
		//cout << "Cost = " << cost << endl;

		for (int i = 0; i < number_vertces; i++)
			if (!visited[i] && arr[C.second][i] > 0)
			{
				Q.push(make_pair(arr[C.second][i], i));
				abo[i] = C.second;
			}
	}


	cout << cost << endl;

	for (int i = 0; i < MST.size(); i++)
	{
		cout << MST[i].from << " " << MST[i].to << " " << MST[i].cost << endl;
	}
	return 0;
}