#include <bits/stdc++.h>
#define INF 1000000007
using namespace std;

ifstream fin("apm.in");
ofstream fout("apm.out");
int n, m, x, y, c, d[200001], viz[200001], start, t[200001], sol;
vector <pair <int, int> >l[200001];
priority_queue< pair<int, int>, vector < pair <int, int> >, greater <pair<int, int> > > q;
int main()
{
    fin>>n>>m;
    for(int i=1; i<=m; i++)
    {
        fin>>x>>y>>c;
        l[x].push_back({y, c});
        l[y].push_back({x, c});
    }
    for(int i=1; i<=n; i++)
    {
        d[i]=INF;
        viz[i]=0;
    }
    t[1]=-1;
    d[1]=0;
    q.push({0, 1});
    while(!q.empty())
    {
        pair <int, int> top=q.top();
        q.pop();
        int nod=top.second;
        if(viz[nod]==1)
            continue;
        viz[nod]=1;
        sol+=d[nod];
        for(int i=0; i<l[nod].size(); i++)
        {
            int vecin=l[nod][i].first;
            int cost=l[nod][i].second;
            if(viz[vecin]==0 && d[vecin]>cost)
            {
                q.push({cost, vecin});
                d[vecin]=cost;
                t[vecin]=nod;
            }
        }
    }
    fout<<sol<<"\n"<<n-1<<"\n";
    for(int i=1; i<=n; i++)
    {
        if(t[i]>0)
        {
            fout<<t[i]<<" "<<i<<"\n";
        }
    }
    return 0;
}