#include<fstream>
#include<algorithm>
#include<vector>
#define pb push_back

using namespace std;

const int maxn = 400100;

int GR[maxn],X[maxn],Y[maxn],C[maxn];
int N,M,ANS,IND[maxn];
vector<int> VANS;

int grupa(int i)
{
	if (GR[i] == i) return i;
	GR[i] = grupa(GR[i]);
	return GR[i];
}
void reuniune(int i,int j)
{
	GR[grupa(i)] = grupa(j); 
}
bool cmpf(int i,int j)
{
	return(C[i] < C[j]);	
}
int main()
{
	ifstream f("apm.in");
	ofstream g("apm.out");
	f>>N>>M;
	for(int i = 1;i <= M;++i)
	{
		f>>X[i]>>Y[i]>>C[i];
		IND[i] = i;
	}
	for(int i = 1;i <= N; ++i) GR[i] = i;

	sort(IND + 1,IND + M + 1,cmpf);
	for(int i = 1;i <= M; ++i)
	{
		if (grupa(X[IND[i]]) != grupa(Y[IND[i]])){
			ANS += C[IND[i]];reuniune(X[IND[i]],Y[IND[i]]);
			VANS.pb(IND[i]);
		}
	}
	g<<ANS<<"\n";
	g<<N - 1<<"\n";
	for(int i = 0;i < N - 1; ++i)
		g<<X[VANS[i]]<<" "<<Y[VANS[i]]<<"\n";
	return 0;
}