#include <bits/stdc++.h>
#define startt ios_base::sync_with_stdio(false);cin.tie(0);
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
typedef unsigned long long ull;
typedef long long  ll;
using namespace std;
#define FOR(n) for(int i=0;i<n;i++)
#define vt vector
#define vint vector<int>
#define all(v) v.begin(), v.end()
#define MOD 1000000007
#define MOD2 998244353
#define MX 1000000000
#define nax 100005
#define MXL 1000000000000000000
#define PI 3.14159265
#define pb push_back
#define pf push_front
#define sc second
#define fr first
#define int ll
#define endl '\n'
#define ld long double

const int MAXARR = 1e4 + 5;
int id[MAXARR], nodes, edges;
pair <long long, pair<int, int> > p[MAXARR];

void initialize()
{
	for(int i = 0;i < MAXARR;++i)
	id[i] = i;
}

int root(int x)
{
	while(id[x] != x)
	{
		id[x] = id[id[x]];
		x = id[x];
	}
	return x;
}

void union1(int x, int y)
{
	int p = root(x);
	int q = root(y);
	id[p] = id[q];
}

vector<pair<int, int>> kruskal(pair<long long, pair<int, int> > p[])
{
	int x, y;
	vector<pair<int, int>> ans;
	long long cost, minimumCost = 0;
	for(int i = 0;i < edges;++i)
	{
		x = p[i].second.first;
		y = p[i].second.second;
		cost = p[i].first;
		if(root(x) != root(y))
		{
			ans.pb({x, y});
			minimumCost += cost;
			union1(x, y);
		}
	}
	cout << minimumCost << endl;
	return ans;
}

int32_t main(){
	startt;
	freopen("apm.in", "r", stdin);
	freopen("apm.out", "w", stdout);
	int x, y;
	long long weight, minimumCost;
	initialize();
	cin >> nodes >> edges;
	for(int i = 0;i < edges;++i)
	{
		cin >> x >> y >> weight;
		p[i] = make_pair(weight, make_pair(x, y));
	}
	sort(p, p + edges);
	vector<pair<int, int>> a = kruskal(p);
	cout << a.size() << endl;
	for(auto p : a)
	{
		cout << p.fr << " " << p.sc << endl;
	}
}