#include <bits/stdc++.h>
#define oo INT_MAX
using namespace std;

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

int n,m;
vector < pair < int, int > > v[200005];
int x,y,c;
priority_queue < pair < int , int > , vector < pair < int , int > > , greater < pair < int , int > > > pq;
int dist[200005],tata[200005],viz[200005];
int totaldist;

void infinity() {
    for (int i=1;i<=n;i++) {
        dist[i] = oo;
    }
}

void create_graph() {
    f  >> n >> m;
    for (int i=1;i<=m;i++) {
        f >> x >> y >> c;
        v[x].push_back({y,c});
        v[y].push_back({x,c});
    }
}

void apm() {
    dist[1]=0;
    pq.push({0,1});
    while (pq.empty()==0) {
        int nod = pq.top().second;
        int distnod = pq.top().first;
        pq.pop();
        if (viz[nod]==0) {
            viz[nod] = 1;
            totaldist += distnod;
            for (int k=0;k<v[nod].size();k++) {
                int nodtoviz = v[nod][k].first;
                int distance = v[nod][k].second;
                if (dist[nodtoviz]>distance && viz[nodtoviz]==0) {
                    dist[nodtoviz] = distance;
                    pq.push({distance,nodtoviz});
                    tata[nodtoviz] = nod;
                }
            }
        }
    }
}

void show() {
    g << totaldist << '\n';
    g << n-1 << '\n';
    for (int i=2;i<=n;i++) {
        g << i << " " << tata[i] << '\n';
    }
}

int main()
{
    create_graph();
    infinity();
    apm();
    show();
    return 0;
}