#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <bitset>
#include <tuple>

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

const int NMAX = 200005;
vector <pair<int, int> > G[NMAX];
priority_queue<tuple<int, int, int> > pq;
bitset <NMAX> viz;
int n, m, s, tata[NMAX];

void citire()
{
    fin>>n>>m;
    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));
    }
}

void apm()
{
    pq.push(make_tuple(0, 1, 0));
    while(!pq.empty())
    {
        int nod=get<1>(pq.top());
        int cost=-get<0>(pq.top());
        int nod2=get<2>(pq.top());
        pq.pop();
        if(viz[nod])
            continue;
        viz[nod]=1;
        tata[nod]=nod2;
        s+=cost;
        for(auto nbr: G[nod])
            if(!viz[nbr.first])
                    pq.push(make_tuple(-nbr.second, nbr.first, nod));
    }
    fout<<s;
}
int main()
{
    citire();
    apm();
    fout<<endl;
    fout<<n-1<<endl;
    for(int i=2; i<=n; ++i)
        fout<<i<<" "<<tata[i]<<endl;
}