#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

vector<pair<int, int>> L[200001];
int d[200001], p[200001], vis[200001];

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

    int n, m;
    fin >> n >> m;

    for (int i = 1; i <= m; i++)
    {
        int x, y, c;
        fin >> x >> y >> c;
        L[x].push_back({y, c});
        L[y].push_back({x, c});
    }

    for (int i = 1; i <= n; i++)
    {
        d[i] = 1e9;
    }
    d[1] = 0;

    int sum = 0;

    priority_queue<pair<int,int>> pq; //(d[nod], nod)
    pq.push({d[1],1});
    while (pq.empty() ==false) {
        //selectam nodul cu d-ul minim
        int nod = pq.top().second;
        if (vis[nod] ==1) {
            continue;
        }
        sum+= d[nod];
        vis[nod]=1;

        for (auto it : L[nod])
        {
            int vec = it.first;
            int cost = it.second;

            if(vis[vec] == 0 && d[vec] > cost) {
                d[vec] = cost;
                p[vec] = nod;
            }
        }
    }

    fout << sum << "\n";
    //afisam (i,p[i]) pt i>=2;
    fout<< n - 1 << "\n";
    for (int i = 2; i <= n; i++)
    {
        fout << i << " " << p[i] << "\n";
    }

    return 0;
}