// PRIM ALGORITHM

#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <assert.h>
#include <limits.h>

#define ll long long

using namespace std;

const int N = 200005;

ifstream fin("apm.in");
ofstream fout("apm.out");

vector<pair<int, int>> g[N];
bool vis[N];
int tata[N], minCost[N];
int n, m;


int main()
{
    fin >> n >> m;
    for(int i = 0; i < m; i++)
    {
        int x, y, c;
        fin >> x >> y >> c;
        g[x].push_back({y, c});
        g[y].push_back({x, c});
    }

    priority_queue<pair<int, int>> heap;
    heap.push({0, 1});
    for(int i = 2; i <= n; i++)
        minCost[i] = INT_MAX;

    int costTotal = 0;
    while(!heap.empty())
    {
        cout << heap.top().second << ' ' << heap.top().first << '\n';
        int nod = heap.top().second;
        int cost = heap.top().first;
        heap.pop();

        if(vis[nod])
            continue;

        vis[nod] = true;
        costTotal -= cost;

        for(auto y : g[nod])
            if(!vis[y.first] && y.second < minCost[y.first])
            {
                heap.push({-y.second, y.first});
                minCost[y.first] = y.second;
                tata[y.first] = nod;
            }
    }

    fout << costTotal << '\n';
    fout << n - 1 << '\n';
    for(int i = 2; i <= n; i++)
        fout << i << ' ' << tata[i] << '\n';

    return 0;
}