#include <stdio.h>
#include <stdlib.h>
#include <math.h>

struct Edge{
        int v,key;
        struct Edge *next;
};
struct Top{
        int v_v,value,index,key;
	struct Edge *next;
} *M,*v,min;
struct PrioQueue{
	struct Top **heap;
	int count;
} q;
int N,E;
void Heapify(int i,int x);
void Insert(int v);
void ExtractMin();
void DecreaseKey(int x,int key);
void AddEdge(int a,int b,int key);
void Edgesfree();
void Edgefree(struct Edge *a);
int main(){
        int i,j=0,k,x,y,z,sum=0,d=10000,f=0;
        scanf(" %d %d",&N,&E);
	struct Edge *s;
	M=malloc(sizeof(struct Top)*N);
	q.heap=malloc(sizeof(struct Top*)*N);
	q.count=0;
	for(i=0;i<N;i++){
		M[i].next=NULL;
		M[i].v_v=i;
		M[i].index=-1;
		M[i].key=-1;
	}
	for(i=0;i<E;i++){
		scanf(" %d %d %d",&x,&y,&z);
		AddEdge(x,y,z);
	}
	v=&M[0];
	for(;;){
		v->index=-2;
		s=v->next;
		while(s!=NULL){
			if (M[s->v].index==-1){
				M[s->v].key=s->key;
				M[s->v].value=v->v_v;
				sum+=s->key;
				Insert(s->v);
			}
			else if (M[s->v].index!=-2 && s->key<M[s->v].key){
				M[s->v].value=v->v_v;
				sum-=M[s->v].key-s->key;
				DecreaseKey(M[s->v].index,s->key);
			}
			s=s->next;
		}
		if (q.count==0)
			break;
		ExtractMin();
		v=&M[min.v_v];
	}
	printf("%d\n",sum);
	Edgesfree();
	free(M);
	return 0;
}

void Heapify(int i,int x){
	int l,r,j,k=i;;
	struct Top *a;
	for(;;){
		l=2*k+1;r=l+1;j=k;
		if(l<x && q.heap[k]->key>q.heap[l]->key)
			k=l;
		if(r<x && q.heap[k]->key>q.heap[r]->key)
			k=r;
		if(k==j)
			break;
		a=q.heap[k];
		q.heap[k]=q.heap[j];
		q.heap[j]=a;
		q.heap[k]->index=k;
		q.heap[j]->index=j;
	}
}

void Insert(int p){
	struct Top *s;
	int i=q.count;
	q.count++;
	q.heap[i]=&M[p];
	while(i>0 && q.heap[(i-1)/2]->key>q.heap[i]->key){
		s=q.heap[(i-1)/2];
		q.heap[(i-1)/2]=q.heap[i];
		q.heap[i]=s;
		q.heap[i]->index=i;
		i=(i-1)/2;
	}
	q.heap[i]->index=i;
}
void ExtractMin(){
	struct Top *a;
	min=*q.heap[0];
	q.count--;
	if (q.count>0){
		q.heap[0]=q.heap[q.count];
		q.heap[0]->index=0;
		Heapify(0,q.count);
	}
}

void DecreaseKey(int x,int key){
	int i=q.heap[x]->index;
	struct Top *s;
	q.heap[x]->key=key;
	while(i>0 && q.heap[(i-1)/2]->key>key){
		s=q.heap[(i-1)/2];
		q.heap[(i-1)/2]=q.heap[i];
		q.heap[i]=s;
		q.heap[i]->index=i;
		i=(i-1)/2;
	}
	q.heap[i]->index=i;
}

void AddEdge(int a,int b,int key){
	struct Edge *s;
	s=M[a].next;
	if(s!=NULL){
		while(s->next!=NULL)
			s=s->next;
		s->next=(struct Edge*)malloc(sizeof(struct Edge));
		s=s->next;
		s->v=b;
		s->key=key;
		s->next=NULL;
	}
	else{
		M[a].next=(struct Edge*)malloc(sizeof(struct Edge));
		M[a].next->v=b;
		M[a].next->key=key;
		M[a].next->next=NULL;
	}
	s=M[b].next;
	if(s!=NULL){
		while(s->next!=NULL)
			s=s->next;
		s->next=(struct Edge*)malloc(sizeof(struct Edge));
		s=s->next;
		s->v=a;
		s->key=key;
		s->next=NULL;
	}
	else{
		M[b].next=(struct Edge*)malloc(sizeof(struct Edge));
		M[b].next->v=a;
		M[b].next->key=key;
		M[b].next->next=NULL;
	}
}

void Edgesfree(){
	int i;
	for(i=0;i<N;i++){
		Edgefree(M[i].next);
	}

}

void Edgefree(struct Edge *a){
	struct Edge *s;
	s=a;
	if(s!=NULL){
		Edgefree(s->next);
		free(s);
	}
}