package algorithm;

import java.util.*;

public class KruskalEdge {

static class Edge implements Comparable<Edge> {

int from, to, weight;

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

this.from = from;

this.to = to;

this.weight = weight;

}

@Override

public int compareTo(Edge o) {

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

}

}

static int N;

static Edge[] edges;

static int[] p;

static void make() {

p = new int[N];

for (int i = 0; i < N; i++)

p[i] = i;

}

static int find(int a) {

if (p[a] == a)

return a;

return p[a] = find(p[a]);

}

static boolean union(int a, int b) {

int ar = find(a);

int br = find(b);

if (ar == br)

return false;

p[br] = p[ar];

return true;

}

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

N = sc.nextInt();

int E = sc.nextInt();

edges = new Edge[E];

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

int from = sc.nextInt();

int to = sc.nextInt();

int weight = sc.nextInt();

edges[i] = new Edge(from, to, weight);

}

Arrays.sort(edges);

make();

int res = 0, cnt = 0;

for (Edge edge : edges) {

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

res += edge.weight;

if (++cnt == N - 1)

break;

}

}

System.out.println(res);

sc.close();

}

}