#include<fstream>
using namespace std;
struct muchie{
	int x,y,c;
};
muchie vm[5000],h[100];
int n,m,ct,c[100];
ifstream in("apm.in");
ofstream out("apm.out");

void citire(){
	in>>n>>m;
	int i;
	for(i=1;i<=m;i++)
		in>>vm[i].x>>vm[i].y>>vm[i].c;
}
void sort(){
	int i,j;
	for(i=1;i<=m;i++)
		for(j=i+1;j<=m;j++)
			if(vm[i].c>vm[j].c){
				muchie aux=vm[i];
				vm[i]=vm[j];
				vm[j]=aux;
			}
}
void apm(){
	for(int i=1;i<=n;i++)
		c[i]=i;
	sort();
	int nsel=0,i=1;
	while(nsel<n-1){
		while(c[vm[i].x]==c[vm[i].y])
			i++;
		nsel++;
		h[nsel]=vm[i];
		int min=c[vm[i].x],max=c[vm[i].x];
		if(c[vm[i].y]>max)max=c[vm[i].y];
		if(c[vm[i].y]<min)min=c[vm[i].y];
		for(int j=1;j<=n;j++)
			if(c[j]==max)
				c[j]=min;
			ct+=vm[i].c;
	}}
int main(){
	citire();
	apm();
	out<<ct<<"\n";
	for(int i=1;i<n;i++)
		out<<h[i].x<<" "<<h[i].y<<" "<<h[i].c<<"\n";
	return 0;
}