#include <bits/stdc++.h>
using namespace std;
//Union_Find
long long ufpar[100005], ufrank[100005];
 
//初期化
void ufinit(int n){
	for(int ii = 1; ii <= n; ii++){
		ufpar[ii] = ii;
		ufrank[ii] = 0;
	}
}
 
//木の根を求める
int uffind(long long x){
	if(ufpar[x] == x) {
		return x;
	} else {
		ufpar[x] = uffind(ufpar[x]);
		return ufpar[x];
	}
}
 
//併合
void ufunite(long long x, long long y){
	x = uffind(x);
	y = uffind(y);
	if(x == y) return;
	if(ufrank[x] < ufrank[y]){
		ufpar[x] = y;
	} else {
		ufpar[y] = x;
		if(ufrank[x] == ufrank[y]) ufrank[y]++;
	}
}
 
//同じ集合か
bool ufsame(long long x, long long y){
	return uffind(x) == uffind(y);
}
 
//Kruskal (Union_Findが必要)
const int max_e=200000;
struct edge { int u, v; long long cost; };
bool comp(const edge& e1, const edge& e2){
    return e1.cost < e2.cost;
}
edge es[max_e]; //各辺の情報を持つ
int v,e; //頂点数、辺数
int kruskal(){
    sort(es, es + e, comp);
    ufinit(v);
    long long res = 0;
    for(int i = 0; i < e; i++){
        edge e = es[i];
        if(!ufsame(e.u, e.v)){
            ufunite(e.u, e.v);
            res += e.cost;
        }
    }
    return res;
}
 
int main (){
	cin >> v >> e;
	edge em;
	for(int i=0;i<e;i++){
		int s,t,w;
		cin >> s >> t >> w;
		em.u=s; em.v=t; em.cost=w;
		es[i]=em;
	}
	cout << kruskal() << endl;
    return 0;
}

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6 9
0 1 1
0 2 3
1 2 1
1 3 7
2 4 1
1 4 3
3 4 1
3 5 1
4 5 6