#include<bits/stdc++.h>
using namespace std;
typedef tuple<int,int,int>T;
typedef vector<T>VT;
int main(void){
	int v,e;
	int s,t,w;
	VT vt;
	T tt;
	int par[10001],ran[10001];
	int x,y;
	int sum;
	int i,j;
	cin>>v>>e;
	for(i=0;i<e;i++){
		cin>>s>>t>>w;
		get<0>(tt)=w;
		get<1>(tt)=s;
		get<2>(tt)=t;
		vt.push_back(tt);
	}
	sort(vt.begin(),vt.end());
	for(i=0;i<v;i++){
		par[i]=i;
		ran[i]=0;
	}
	sum=0;
	for(i=0;i<e;i++){
		x=get<1>(vt[i]);
		y=get<2>(vt[i]);
		while(x!=par[x])	x=par[x];
		while(y!=par[y])	y=par[y];
		if(x!=y){
			if		(ran[x]<ran[y])	par[x]=y;
			else if	(ran[x]>ran[y])	par[y]=x;
			else{	
				par[x]=y;
				ran[y]++;
			}
			sum+=get<0>(vt[i]);
		}
	}
	cout<<sum<<endl;
	return 0;
}
