package algorithm;

import java.util.Arrays;

import java.util.Scanner;

public class MSTTest1 {

static class Edge implements Comparable<Edge> {

int from, to, weight;

public Edge(int from, int to, int weight) {

super();

this.from = from;

this.to = to;

this.weight = weight;

}

@Override

public int compareTo(Edge o) {

return Integer.compare(this.weight, o.weight);

}

}

static void makeSet() {

parents = new int[V];

for (int i = 0; i < V; i++) {

parents[i] = i;

}

}

static int findSet(int a) {

if (parents[a] == a)

return a;

return parents[a] = findSet(parents[a]);

}

static boolean unionSet(int a, int b) {

int ar = findSet(a);

int br = findSet(b);

if (ar == br)

return false;

parents[br] = ar;

return true;

}

static int V, E;

static Edge[] edgelist;

static int[] parents;

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

V = sc.nextInt();

E = sc.nextInt();

edgelist = new Edge[E];

for (int i = 0; i < E; i++) {

edgelist[i] = new Edge(sc.nextInt(), sc.nextInt(), sc.nextInt());

}

Arrays.sort(edgelist);

makeSet();

int res = 0, cnt = 0;

for (Edge edge : edgelist) {

if (unionSet(edge.from, edge.to)) {

res += edge.weight;

if (++cnt == V - 1)

break;

}

}

System.out.println(res);

sc.close();

}

}