#include<fstream>
#include<cstdio>
#include<set>
#include<vector>
#include<algorithm>
#define FOR(a,b,c) for(int a=b;a<=c;++a)
#include<cstring>
#include<bitset>
#include<cmath>
#include<iomanip>
#include<queue>
#define f cin
#define g cout
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define ll long long
#define bit 20
#define inf (1<<30)
#define base 256
#define ba 255
#define N 200100
#define mod  1999999973
#define inu "apm.in"
#define outu "apm.out"
using namespace std;
ifstream f(inu);
ofstream g(outu);
//int dx[]={0,0,0,1,-1};
//int dy[]={0,1,-1,0,0};
vector<pair<int,int> > v[N];
int D[N],n,cost,m,nod,viz[N],x,y,c,T[N];
priority_queue<pair<int,int>,vector<pair<int,int> > >pq;
int main ()
{
    f>>n>>m;
    FOR(i,1,m)
    {
        f>>x>>y>>c;
        v[x].pb(mp(y,c));
        v[y].pb(mp(x,c));
    }
    FOR(i,2,n)
    D[i]=inf;
    pq.push(mp(0,1));
    while(!pq.empty())
    {
        while(!pq.empty()&&viz[pq.top().se])
        pq.pop();
        if(pq.empty())
        break;
        nod=pq.top().second;
        cost+=D[nod];
        viz[nod]=1;
        pq.pop();
        for(int i=0;i<v[nod].size();++i)
        {
            int de=v[nod][i].fi;
            int co=v[nod][i].se;
            if(!viz[de]&&co<D[de])
            {
                T[de]=nod;
                D[de]=co;
                pq.push(mp(-D[de],de));
            }
        }
    }
    g<<cost<<"\n";
    g<<n-1<<"\n";
    FOR(i,2,n)
    g<<i<<" "<<T[i]<<"\n";
    return 0;
}