#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <fstream>
#include <iterator>
#include <random>
#include <assert.h>
using namespace std;

const string file = "apm";

const string infile = file + ".in";
const string outfile = file + ".out";

const int INF = 0x3f3f3f3f; 

//#define ONLINE_JUDGE



int main()
{
#ifdef ONLINE_JUDGE
	ostream &fout = cout;
	istream &fin = cin;
#else
	fstream fin(infile.c_str(), ios::in);
	fstream fout(outfile.c_str(), ios::out);
#endif	

    int N, M;
    fin >> N >> M;
    vector<vector<pair<int, int> > > G(N + 1);
    for(int i = 0; i < M; i++)
    {
        int x, y, c;
        fin >> x >> y >> c;
        G[x].push_back(make_pair(y, c));
        G[y].push_back(make_pair(x, c));
    }


    priority_queue<pair<int, int>, vector<pair<int, int> > , greater<pair<int, int> > > heap;

    vector<int> dist(N + 1, INF);
    vector<int> prec(N + 1);
    vector<bool> viz(N + 1, false);

    heap.push(make_pair(0, 1));
    dist[1] = 0;

    int Sol = 0;

    while(heap.empty() == false)
    {

        pair<int, int> c = heap.top();
        heap.pop();
        int d = c.first;
        int x = c.second;
    
        if(dist[x] != d || viz[x])
            continue;
        Sol += d;
        viz[x] = true;
        for(vector<pair<int, int> >::iterator itr = G[x].begin();
                itr != G[x].end();
                itr++)
        {
            int dst = itr->first;
            int cst = itr->second;
            if(viz[dst] == false && dist[dst] > cst)
            {
                prec[dst] = x;
                dist[dst] = cst;

                heap.push(make_pair(dist[dst], dst));

            }
        }
    }

    fout << Sol << "\n";

    fout << N - 1 << "\n";
    for(int i = 2; i <= N; i++)
    {
        fout << prec[i] << " " << i << "\n";
    }
#ifdef ONLINE_JUDGE
#else
    fout.close();
	fin.close();
#endif
}