#include <cstdio>
#include <cstring>
#include <string>
#include <cmath>
#include <cstdlib>
#include <map>
#include <set>
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;


struct edge {
    int from;
    int to;
    int weight;
    bool inline friend operator < (edge x, edge y)
    {
        if (x.weight < y.weight)
            return true;
        return false;
    }
} edges[4500000];
int parent[3001];

int findSet(int x)
{
    if (parent[x] == x)
        return x;
    return parent[x] = findSet(parent[x]);
}

int main()
{
    int n,m;
    cin >> n >> m;

    for (int i=0;i<m;i++)
    {
        int f,t,w;
        cin >> f >> t >> w;
        edges[i].from = f;
        edges[i].to = t;
        edges[i].weight = w;
    }
    sort(edges , edges + m);

    for (int i=1;i<=n;i++)
        parent[i] = i;
    int cnt = n, cur = 0;
    int sum = 0;
    while (cnt != 1)
    {
        if (findSet(edges[cur].from) != findSet(edges[cur].to))
        {
            parent[findSet(edges[cur].to)] = findSet(edges[cur].from);
            sum += edges[cur].weight;
            cnt--;
        }
        cur++;
    }

    cout << sum;
}