#include<iostream>
#include<algorithm>
using namespace std;
struct node{int x,y,w;};
node bian[10001];
int fa[10001],sum,num;// 
int bcj(int x){
	if(fa[x]==x)return x;
	fa[x]=bcj(fa[x]);
	return fa[x]; 
}
bool cmp(node x,node y){
	if(x.w<y.w)return 1;
	else return 0; 
}
int main(){
	int n,m;
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		int x,y,z;
		cin>>x>>y>>z;
		bian[i].x=x;
		bian[i].y=y;
		bian[i].w=z;
	}
	sort(bian+1,bian+1+m,cmp);
	for(int i=1;i<=n;i++)
		fa[i]=i;
//	for(int i=1;i<=m;i++)
//		cout<<bian[i].x<<"---"<<bian[i].y<<' '<<bian[i].w<<endl;
	for(int i=1;i<=m;i++){
		int x=bian[i].x;
		int y=bian[i].y;
		int a=bcj(x);
		int b=bcj(y);
		if(a==b)continue;
		sum+=bian[i].w;
		num++;
		if(num==n-1)break;
	}
//	for(int i=1;i<=n;i++)
//		cout<<i<<"fa:"<<fa[i]<<endl;
	cout<<sum;
	return 0;
}