#include <iostream>
#include <fstream>
#define INFINIT 1000000000
using namespace std;

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

struct muchie{
    int i,j,cost;
};

int n , m , t[105];

muchie x[5000];
int v[5000];

int main()
{
    fin >> n >> m;

    for(int i = 0 ; i < m ; ++i)
        fin >> x[i].i >> x[i].j >> x[i].cost;

    for(int i = 0 ; i < m - 1; i ++)
        for(int j = i + 1 ; j < m ; ++j)
            if(x[i].cost > x[j].cost)
            {
                muchie aux = x[i];
                x[i] = x[j];
                x[j] = aux;
            }
    for(int i =1 ; i <= n ; ++i)
        t[i] = i;
    int S = 0, cnt = 0;
    for(int i = 0 ; i < m && cnt < n ; i ++)
        if(t[x[i].i] != t[x[i].j])
        {
            v[i] = 1;
            S += x[i].cost;
            int ai = t[x[i].i], aj = t[x[i].j];
            for(int j =1 ; j <= n ; ++j)
                if(t[j] == aj)
                    t[j] = ai;
        }
    fout << S << "\n";
    for(int i = 0 ; i < m ; ++i)
        if(v[i] == 1)
            fout << x[i].i << " " << x[i].j << "\n";
    return 0;
}