#include <iostream>
#include <fstream>
#include <vector>
#include <set>
#define NMAX 200005
#define INF 99999999
using namespace std;
ifstream f("apm.in");
ofstream g("apm.out");
int d[NMAX],tata[NMAX],s,i,x,y,c,viz[NMAX],n,m,nod;
vector < pair<int,int> > a[NMAX];
struct comp
{
    bool operator () (const int &a,const int &b)
    {
        return d[a]<d[b];
    }
};
set <int,comp> Set;
int main()
{
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y>>c;
        a[x].push_back({y,c});
        a[y].push_back({x,c});
    }
    for(i=1;i<=n;i++)
    {
        d[i]=INF;
    }
    d[1]=0;
    viz[1]=1;
    for(i=0;i<a[1].size();i++)
    {
        d[a[1][i].first]=a[1][i].second;
        tata[a[1][i].first]=1;
        Set.insert(a[1][i].first);
    }
    while(!Set.empty())
    {
        nod=*Set.begin();
        Set.erase(Set.begin());
        viz[nod]=1;
        //s=s+d[i];
        //cout<<nod<<"\n";
        //s=s+d[nod];
        //cout<<nod<<"\n";
        for(i=0;i<a[nod].size();i++)
        {
            if(viz[a[nod][i].first]==0 && d[a[nod][i].first]>a[nod][i].second)
            {
                d[a[nod][i].first]=a[nod][i].second;
                tata[a[nod][i].first]=nod;
                Set.insert(a[nod][i].first);
            }
        }
    }
    for(i=1;i<=n;i++)
    {
        s=s+d[i];
        //cout<<d[i]<<" ";
    }
    g<<s<<"\n";
    g<<n-1<<"\n";
    for(i=2;i<=n;i++)
    {
        g<<i<<" "<<tata[i]<<"\n";
    }
    return 0;
}