#include <iostream>
#include <vector>
#include <stack>
#include <queue>
#include <fstream>
const int INF = 10000000;

std::ifstream input("spantree2.in");
std::ofstream output("spantree2.out");
int primMST(int &n, int &m, std::vector < std::vector < std::pair <int, int>>> &Table)
{

    std::priority_queue< std::pair<int,int>, std::vector <std::pair<int,int>>, std::greater<std::pair<int,int>>> pq;

    int src = 0;

    std::vector<int> key;
    key.resize(n, INF);


    std::vector<bool> inMST;
    inMST.resize(n, false);

    pq.push(std::make_pair(0, src));
    key[src] = 0;

    int res = 0;

    while (!pq.empty())
    {
        int u = pq.top().second;
        pq.pop();

        inMST[u] = true;

        for (int i = 0; i < (int)Table[u].size(); i++)
        {
            int v = Table[u][i].first;
            int weight = Table[u][i].second;

            if (inMST[v] == false && key[v] > weight)
            {
                key[v] = weight;
                pq.push(std::make_pair(key[v], v));
            }
        }
    }

    for (int i = 0; i < (int)key.size(); i++)
        res += key[i];

    output << res;

    return 0;
}

int main() {
    std::vector < std::vector < std::pair <int, int>>> Table;
    std::pair<int,int> Pairs_of_elements;
    int n, m;
    input >> n >> m;
    Table.resize(n);
    for (int i = 0; i < m; i++)
    {
        int u, v, w;
        input >> u >> v >> w;
        u--;
        v--;
        Table[u].push_back({ v, w });
        Table[v].push_back({ u, w });
    }

    primMST(n, m, Table);


    return 0;
}