#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream f("apm.in");
ofstream g("apm.out");
vector <pair<int,int> > a[200010];
pair <int,int> per;
int s=10000,rez[200010],i,j,k,v[200010],viz[200010],h[200010],n,poz[200010],m,x,y,b,z,c;
void verif(int nod)
{
    int aux,nr;
    nod=poz[nod];
    while(v[h[nod]]<v[h[nod/2]])
    {
        aux=h[nod];
        h[nod]=h[nod/2];
        h[nod/2]=aux;
        poz[h[nod]]=nod;
        poz[h[nod/2]]=nod/2;
        nod/=2;
    }
    while(v[h[nod]]>v[h[nod*2]]||v[h[nod]]>v[h[nod*2+1]])
    {
        if(v[h[nod*2]]<v[h[nod*2+1]])
            nr=nod*2;
        else
            nr=nod*2+1;
        aux=h[nod];
        h[nod]=h[nr];
        h[nr]=aux;
        poz[h[nod]]=nod;
        poz[h[nr]]=nr;
        nod=nr;
    }
}
int main()
{
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y>>z;
        a[x].push_back(pair<int,int>(y,z));
        a[y].push_back(pair<int,int>(x,z));
    }
    h[1]=1;
    v[1]=-10000;
    for(i=2;i<=n;i++)
    {
        h[i]=i;
        poz[i]=i;
        v[i]=10000;
    }
    v[0]=100000;
    v[200001]=-100000;
    h[0]=200001;
    poz[1]=1;
    k=n;
    z=0;
    while(k)
    {
        x=h[1];
        viz[x]=1;s+=v[x];
        rez[x]=z;
        z=x;
        h[1]=h[k];
        h[k]=0;
        poz[h[1]]=1;
        verif(h[1]);
        k--;
        for(vector<pair<int,int> >::iterator it=a[x].begin();it!=a[x].end();it++)
        {
            per=*it;
            c=per.first;
            b=per.second;
            if(!viz[c]&&b<v[c])
            {
                v[c]=b;
                verif(c);
            }
        }
    }
    g<<s<<'\n'<<n-1<<'\n';
    while(rez[z])
    {
        g<<z<<" "<<rez[z]<<'\n';
        z=rez[z];
    }
    return 0;
}