#include <bits/stdc++.h>
#define Nmax 105
using namespace std;
ifstream fin("kruskal.in");
ofstream fout("kruskal.out");
struct muchie
{
    int x, y, cost;
} aux;
int N, M;
int total;
int tata[Nmax];
int rang[Nmax];

struct rezultate
{
    int x, y;
} keep;
vector<rezultate>rez;
int cmp(muchie a, muchie b)
{
    return a.cost < b.cost;
}
vector<muchie>v;
int father(int nod)
{
    while(tata[nod] != nod)
        nod = tata[nod];
    return nod;
}
void unire(int x, int y)
{
    tata[x] = y;
}
void afisare()
{
    fout<<total<<"\n";
    for(auto i=0; i<rez.size(); i++)
    {
        fout<<rez[i].x<<" "<<rez[i].y<<"\n";
    }
}
void rezolvare()
{
    int contor = 0;
    int tatal_x, tatal_y;
    for(int i=0; i<M; i++)
    {
        tatal_x = father(v[i].x);
        tatal_y = father(v[i].y);

        if(tatal_x != tatal_y)
        {
            unire(tatal_x, tatal_y);

            ++contor;
            keep.x = v[i].x;
            keep.y = v[i].y;

            rez.push_back(keep);

            total += v[i].cost;
            if(contor == N - 1)
            {
                break;
            }

        }
    }
    afisare();
}
void initializare()
{
    for(int i=1; i<=N; i++)
    {
        tata[i] = i;
        rang[i] = 1;
    }
}
void citire()
{
    fin>>N>>M;
    int a, b, c;
    for(int i=1; i<=M; i++)
    {
        fin>>a>>b>>c;
        aux.x = a;
        aux.y = b;
        aux.cost = c;
        v.push_back(aux);
    }
    sort(v.begin(), v.end(), cmp);

    initializare();
    rezolvare();
}
int main()
{
    citire();
    return 0;
}