#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#define N 200000
#define M 400000
#define INF (1 << 30)

typedef struct
{
    int vf, c, urm;
} element;

int lst[N+1], n, m, nr, nh, d[N+1], h[N+1], poz[N+1], pred[N+1];
element v[M+1];

void adauga(int x, int y, int c)
{
    //adauga pe y in lista de adiacenta a lui x
    v[++nr].vf = y;
    v[nr].c = c;
    v[nr].urm = lst[x];
    lst[x] = nr;
}

void initializeaza(int x0)
{
    for (int i = 1; i <= n; i++)
    {
        d[i] = INF;
    }
    d[x0] = 0;
}

void schimba(int p1, int p2)
{
    int aux = h[p1];
    h[p1] = h[p2];
    h[p2] = aux;
    poz[h[p1]] = p1;
    poz[h[p2]] = p2;
}

void urca(int p)
{
    while (p > 1 && d[h[p]] < d[h[p/2]])
    {
        schimba(p, p/2);
        p /= 2;
    }
}

void coboara(int p)
{
    int fs = 2*p, fd = 2*p+1, optim = p;
    if (fs <= nh && d[h[fs]] < d[h[optim]])
    {
        optim = fs;
    }
    if (fd <= nh && d[h[fd]] < d[h[optim]])
    {
        optim = fd;
    }
    if (optim != p)
    {
        schimba(p, optim);
        coboara(optim);
    }
}

void adauga_h(int x)
{
    h[++nh] = x;
    poz[x] = nh;
    urca(nh);
}

void sterge_h()
{
    schimba(1, nh--);
    if (nh == 0)
    {
        return;
    }
    coboara(1);
}

int apm()
{
    int x0 = 1, cost = 0;
    initializeaza(x0);
    adauga_h(x0);
    while (nh > 0)//cat timp h nu e vid
    {
        int x = h[1];
        cost += d[x];
        sterge_h();
        for (int p = lst[x]; p != 0; p = v[p].urm)//parcurgem succesorii lui x
        {
            int y = v[p].vf;
            int c = v[p].c;
            if (c < d[y])
            {
                d[y] = c;
                pred[y] = x;
                if (poz[y] != 0)//y este deja in heap
                {
                    urca(poz[y]);
                }
                else
                {
                    adauga_h(y);
                }
            }
        }
    }
    return cost;
}

int main()
{
    FILE *in, *out;
    in = fopen("apm.in", "r");
    out = fopen("apm.out", "w");
    fscanf(in, "%d%d", &n, &m);
    for (int i = 0; i < m; i++)
    {
        int x, y, c;
        fscanf(in, "%d%d%d", &x, &y, &c);
        adauga(x, y, c);
        adauga(y, x, c);
    }
    fclose(in);
    fprintf(out, "%d\n%d\n", apm(), n - 1);
    for (int i = 2; i <= n; i++)
    {
        fprintf(out, "%d %d\n", pred[i], i);
    }
    fclose(out);
    return 0;
}