#include <algorithm>
#include <fstream>
#include <iostream>
#include <queue>
#include <vector>
#include <tuple>

using namespace std;

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

constexpr int INF = 1e9;
int main(){
    int n,m;
    fin >> n>>m;
    vector<vector<pair<int,int>>> lista(n+1);
    vector<pair<int,int>> rez;
    vector<bool> viz(n+1, false);
    vector<int> dist(n+1, INF);
    int costtotal=0;
    for (int i = 0; i<m; i++) {
        int u,v,c;
        fin>>u>>v>>c;
        lista[u].emplace_back(v,c);
        lista[v].emplace_back(u,c);
    }

    priority_queue< tuple<int,int,int>, vector<tuple<int,int,int>>, greater<>> pq; // cost, u,v
    pq.emplace(0,1,-1);
    // viz[1] = true;
    dist[1] = 0;
    while (!pq.empty()) {
        auto [cost,u,tata] = pq.top();
        pq.pop();

        if (viz[u]) continue;
        if (tata != -1) {
            rez.emplace_back(u,tata);
            costtotal += cost;
        }
        viz[u] = true;
        for (auto [v,c] : lista[u]) {
            if (!viz[v] && dist[v] >= c) {
                pq.emplace(c,v,u);
                dist[v] = c;
            }
        }
    }

    fout<<costtotal<<endl<<rez.size()<<endl;
    for (auto r: rez) {
        fout<<r.first<<" "<<r.second<<endl;
    }




    return 0;
}