#include <iostream>
#include <fstream>
#include <algorithm>
#include <vector>
#define pb push_back
using namespace std;

pair <int,int>p[400010];
int k,n,m,tot,t[200010],r[200010];

struct muchie
{
    int st,dr,cost;
};
vector <muchie> v;

bool cmp(muchie a, muchie b)
{
    return a.cost<b.cost;
}
void citire()
{
    ifstream x("apm.in");
    x>>n>>m; int a,b,c,i;
    for(i=0;i<m;i++){
        x>>a>>b>>c;
        v.pb({a,b,c});
    }
    sort(v.begin(),v.end(),cmp);
    for(i=1;i<=n;i++)
        t[i]=i,r[i]=1;
    x.close();
}

int tata(int nod){
    while(t[nod]!=nod)
        nod=t[nod];
    return nod;
}

void uni(int noda,int nodb)
{
    if(r[noda]<r[nodb]) t[noda]=nodb;
    else if(r[noda]>r[nodb]) t[nodb]=noda;
    else t[noda]=nodb,r[nodb]++;
}

void solve()
{
    int t1,t2;
    for(int i=0;i<m;i++)
    {
        t1=tata(v[i].st); t2=tata(v[i].dr);
        if(t1!=t2)
        {
            uni(t1,t2);
            p[++k].first=v[i].st;
            p[k].second=v[i].dr;
            tot+=v[i].cost;
        }
    }
}

void afis()
{
    ofstream y("apm.out");
    y<<tot<<"\n";
    y<<n-1<<"\n";
    for(int i=1;i<n;i++)
        y<<p[i].first<<" "<<p[i].second<<"\n";
    y.close();
}

int main()
{
    citire();
    solve();
    afis();
}