#include<bits/stdc++.h>
# define INF 0x3f3f3f3f
#define NMAX 200005
#include <fstream>
using namespace std;
ifstream f("apm.in");
ofstream g("apm.out");
int d[NMAX],tata[NMAX],sol;
bool viz[NMAX];
vector < pair<int,int> > a[NMAX];
priority_queue < pair<int,int>,vector < pair<int,int> > ,greater <pair<int,int> > > pq;
int main()
{
    int n,m,x,y,c,i,nod;
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y>>c;
        a[x].push_back({y,c});
        a[y].push_back({x,c});
    }
    for(i=1;i<=n;i++)
    {
        d[i]=INF;
    }
    d[1]=0;
    pq.push({0,1});
    while(!pq.empty())
    {
        nod=pq.top().second;
        pq.pop();
        if(viz[nod]==1)
            continue;
        viz[nod]=1;
        sol=sol+d[nod];
        for(i=0;i<(int)a[nod].size();i++)
        {
            if(viz[a[nod][i].first]==0 && d[a[nod][i].first]>a[nod][i].second)
            {
                d[a[nod][i].first]=a[nod][i].second;
                tata[a[nod][i].first]=nod;
                pq.push({d[a[nod][i].first],a[nod][i].first});
            }
        }
    }
    g<<sol<<"\n";
    g<<n-1<<"\n";
    for(i=2;i<=n;i++)
    {
        g<<tata[i]<<" "<<i<<"\n";
    }
    return 0;
}