//#include <fstream>
#include <cstdio>
#define IN "apm.in"
#define OUT "apm.out"
#define NMAX 100001
using namespace std;


struct mu
{
    int inceput;
    int sfarsit;
    int cost;
};
mu muchie[2*NMAX];

int n,m;
int c[NMAX],solutie[2*NMAX];

void citire();
void rezolva();
void sortare();
void afisare();

int main()
{
    citire();
    rezolva();
    afisare();
    return 0;
}


void citire()
{
    FILE*fin=fopen(IN,"r");
    int i;
    fscanf(fin,"%d",&n);
    //fin>>n;
    fscanf(fin,"%d",&m);
    //fin>>m;
    for(i=1; i<=m; i++)
    {
        fscanf(fin,"%d",&muchie[i].inceput);
        fscanf(fin,"%d",&muchie[i].sfarsit);
        fscanf(fin,"%d",&muchie[i].cost);
        /*
        fin>>muchie[i].inceput;
        fin>>muchie[i].sfarsit;
        fin>>muchie[i].cost;
        */
    }
}


void rezolva()
{
    sortare();
    int i,ramas=0,k,ok,mini,maxi;
    for(i=1; i<=n; i++) c[i]=i;

    for(i=1; i<n; i++)
    {
        ok=1;
        while(ok==1)
        {
            ramas++;
            if(c[ muchie[ramas].inceput] != c[muchie[ramas].sfarsit])
            {
                ok=0;
                solutie[i]=ramas;
                solutie[0]=muchie[ramas].cost+solutie[0];
                mini=c[muchie[ramas].inceput];
                maxi=c[muchie[ramas].sfarsit];

                if(maxi<mini)
                {
                    mini=c[muchie[ramas].sfarsit];
                    maxi=c[muchie[ramas].inceput];
                }
                for(k=1; k<=n; k++) if(c[k]==maxi) c[k]=mini;
            }
        }
    }

}



void sortare()
{
    mu aux;
    int ok=0,i;
    while(ok==0)
    {
        ok=1;
        for(i=1; i<m; i++)
            if(muchie[i].cost > muchie[i+1].cost)
            {
                ok=0;
                aux=muchie[i];
                muchie[i]=muchie[i+1];
                muchie[i+1]=aux;
            }
    }
}
void afisare()
{
    int i;
    FILE*fout=fopen(OUT,"w");
    fprintf(fout,"%d\n",solutie[0]);
    /*
    fout<<solutie[0];
    fout<<'\n';*/
    fprintf(fout,"&d\n",n-1);
    //fout<<n-1<<'\n';

    for(i=1; i<n; i++)
        fprintf(fout,"%d %d\n",muchie[solutie[i]].inceput,muchie[solutie[i]].sfarsit);
        //fout<< muchie[solutie[i]].inceput<<' '<<muchie[solutie[i]].sfarsit<<'\n';
}