// Algoritmul lui Prim
#include<fstream>
#include<algorithm>
#include<vector>
#define pb push_back
#define mkp make_pair
using namespace std;
ifstream f("apm.in"); ofstream g("apm.out");
const int maxn = 200200;
const int INF = 200000200;
int VEC[maxn],ANS,V[maxn],H[maxn * 2 + 100],POZ[maxn];
vector <pair<int,int> > VECT[maxn],VANS;
int N,M,L,C[maxn];
void introduce_in_apm(int x)
{	for(unsigned int i = 0;i < VECT[x].size(); ++i)
    {	int nod = VECT[x][i].first;
		int cost = VECT[x][i].second;
		V[nod] = min(V[nod],cost);
		if (V[nod] == cost) VEC[nod] = x;
 	}
}
void push(int poz)
{	while((poz * 2 <= L && V[H[poz]] > V[H[poz * 2]]) || (poz * 2 + 1 <= L && V[H[poz]] > V[H[poz * 2 + 1]]))
	{if (V[H[poz * 2]] < V[H[poz * 2 + 1]] || poz * 2 + 1 > L)			
		{	swap(H[poz],H[poz * 2]);
			swap(POZ[H[poz]],POZ[H[poz * 2]]);
			poz *= 2;
		}
		else 
		{	swap(H[poz],H[poz * 2 + 1]);
            swap(POZ[H[poz]],POZ[H[poz * 2 + 1]]);
			poz = poz * 2 + 1;
		}
	}
}
void pop(int poz)
{	while(poz > 1 && V[H[poz]] < V[H[poz / 2]])
	{	swap(H[poz],H[poz / 2]);
		swap(POZ[H[poz]],POZ[H[poz / 2]]);
		poz = poz / 2;
	}
}
void introduce_in_heap(int nod)
{	H[++L] = nod;
	POZ[nod] = L;
	pop(L);
}
int scoate_radacina_heap()
{	int x = H[1];
	swap(H[1],H[L]);
	swap(POZ[H[1]],POZ[H[L]]);
	L--;
	push(1);
        POZ[x] = 0;
	return x;
}
int main()
{	f>>N>>M; //scanf("%d %d\n",&N,&M);
	for(int i = 1;i <= M; ++i)
	{	int x,y,c;
		f>>x>>y>>c;//scanf("%d %d %d",&x,&y,&c);
		VECT[x].pb(mkp(y,c)); VECT[y].pb(mkp(x,c));
	}
	for(int i = 1; i <= N; ++i) V[i] = INF;
	V[1] = 0;
	introduce_in_apm(1);
	for(int i = 2;i <= N; ++i) introduce_in_heap(i);
	for(int i = 1;i < N; ++i)
	{	int x = scoate_radacina_heap();
		introduce_in_apm(x);
		ANS += V[x];
		VANS.pb(mkp(x,VEC[x]));
		for(unsigned int j = 0;j < VECT[x].size(); ++j)
		{	int nod = VECT[x][j].first;
			if (POZ[nod]) pop(POZ[nod]);
		}
	}
	g<<ANS<<'\n'<<N-1<<'\n';
	//printf("%d\n",ANS);
	//printf("%d\n",N-1);
	for(int i = 0; i < N - 1; ++i)
		g<<VANS[i].first<<' '<<VANS[i].second<<'\n';	
		//printf("%d %d\n",VANS[i].first,VANS[i].second);
	g.close(); return 0;
}