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

ifstream f("apm.in");
ofstream g("apm.out");

const int INF = 1e9;

int main()
{
    int n, m;
    f >> n >> m;

    vector<vector<pair<int, int>>> graf(n + 1);

    for(int i = 0; i < m; ++i)
    {
        int x, y, c;
        f >> x >> y >> c;
        graf[x].push_back({y, c});
        graf[y].push_back({x, c});
    }

    vector<int> d(n + 1, INF);     
    vector<int> p(n + 1, -1);
    vector<bool> vis(n + 1, false);

    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<>> pq;

    long long cost_total = 0;

    d[1] = 0;
    pq.push({0, 1});

    while(!pq.empty())
    {
        auto [cost, nod] = pq.top();
        pq.pop();

        if(vis[nod])
            continue;

        vis[nod] = true;
        cost_total += d[nod];

        for(auto [vecin, c] : graf[nod])
        {
            if(!vis[vecin] && c < d[vecin])
            {
                d[vecin] = c;
                p[vecin] = nod;
                pq.push({d[vecin], vecin});
            }
        }
    }

    g << cost_total << endl;
    g << n - 1 << endl;

    for(int i = 2; i <= n; ++i)
    {
        g << p[i] << ' ' << i << endl;
    }

    return 0;
}