aa

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import static java.lang.Integer.parseInt;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.StringTokenizer;

public class MST_Minimum_Spanning_Tree {

    static BufferedReader reader;
    static StringTokenizer tok;
    static int n, m;
    static double cost[], wieght[];
    static ArrayList<pair> graph[];
    static PriorityQueue<pair2> q;
    static boolean visited[];

    public static void main(String[] args) throws IOException {
//        BufferedWriter writer = new BufferedWriter(new FileWriter("etex.txt"));
//        writer.write(100000 + " " + 100000);
//        writer.newLine();
//        for (int i = 1; i < 100000; i++) {
//            writer.write(i + " " + (i + 1) + " " + 1000000);
//            writer.newLine();
//            //System.out.println(i + " " + (i + 1) + " " + 1000000);
//        }
        Input();
        sol();
    }

    public static void Input() throws IOException {
       reader = new BufferedReader(new InputStreamReader(System.in));
      //    reader = new BufferedReader(new FileReader("etex.txt"));

        tok = new StringTokenizer(reader.readLine());
        n = parseInt(tok.nextToken());
        m = parseInt(tok.nextToken());
        graph = new ArrayList[n + 1];
        for (int i = 1; i <= n; i++) {
            graph[i] = new ArrayList<pair>();
        }
        for (int i = 1; i <= m; i++) {
            tok = new StringTokenizer(reader.readLine());
            int x = parseInt(tok.nextToken()), y = parseInt(tok.nextToken()), w = parseInt(tok.nextToken());
           System.out.println(x + "  "+y);

            graph[x].add(new pair(y, w));
            graph[y].add(new pair(x, w));
        }
    }

    public static void sol() {

        cost = new double[n + 1];
        wieght = new double[n + 1];

        visited = new boolean[n + 1];
        q = new PriorityQueue<pair2>(Comparator.comparing((pair2 obj) -> obj.weight));
        q.add(new pair2(1, 0));
        visited[1] = true;

        while (!q.isEmpty()) {

            pair2 obj = q.poll();

            for (pair i : graph[obj.node]) {
                if (!visited[i.node]) {
                    visited[i.node] = true;

                    cost[i.node] = (i.weight + obj.weight);
                    wieght[i.node] = i.weight;
                    cost[0] += i.weight;
                    q.add(new pair2(i.node, cost[i.node]));
                } else if (cost[i.node]  > i.weight + obj.weight) {
                    cost[0] -= wieght[i.node];
                    wieght[i.node] = i.weight;
                    cost[i.node] = (i.weight + obj.weight);
                    cost[0] += wieght[i.node];
                    q.add(new pair2(i.node, cost[i.node]));
                }
            }

        }

        System.out.println((int) (cost[0]));

    }

    static class pair {

        int node, weight;

        public pair(int node, int weight) {
            this.node = node;
            this.weight = weight;
        }

    }

    static class pair2 {

        int node;
        double weight;

        public pair2(int node, double weight) {
            this.node = node;
            this.weight = weight;
        }

    }
}

/*

4 5
1 2 10
2 3 15
1 3 5
4 2 2
4 3 40


4 5
1 2 10
2 3 1
1 3 5
4 2 2
4 3 40

4 5
1 2 10
2 3 4
1 3 5
4 2 2
4 3 1


4 5
1 2 2
2 3 2
1 3 2
4 2 2
4 3 3

 */