#include<fstream>
#include<algorithm>
#include<vector>
using namespace std;
ifstream cin("apm.in");
ofstream cout("apm.out");
int n,m,nr,t[200005];
struct arb{
    int x,y,c;
    bool fol;
}a[400005],b[400005];

bool cmp(arb a,arb b)
{
    return a.c<b.c;
}
void afis()
{
    cout<<nr<<"\n";
    for(int i=1;i<=nr;i++)
        cout<<b[i].x<<" "<<b[i].y<<endl;
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        cin>>a[i].x>>a[i].y>>a[i].c;
    }
    sort(a+1,a+m+1,cmp);
    for(int i=1;i<=n;++i)
        t[i]=i;
    int S=0;
    for(int i=1;i<=m;i++)
        if(t[a[i].x]!=t[a[i].y])
        {
            S+=a[i].c;
            b[++nr]=a[i];
            int ai=t[a[i].x],aj=t[a[i].y];
            for(int j=1;j<=n;++j)
                if(t[j]==aj)
                    t[j]=ai;
        }
    cout<<S<<"\n";
    afis();
}