#include <fstream>
#include <vector>
#include <algorithm>
#include <numeric>

using namespace std;

std::vector<short> id;

inline short root(short &i) {
    while (i != id[i]) {
        id[i] = id[id[i]];
        i = id[i];
    }
    return i;
}

int main() {
    std::ifstream fin("spantree2.in");
    std::ofstream fout("spantree2.out");
    std::ios_base::sync_with_stdio(false);
    fin.tie(nullptr);

    short n;
    short x, y;
    int w, m;
    std::vector<std::pair<int, std::pair<short, short>>> adj;

    int mst = 0;

    fin >>n>>m;
    n += 1;

    while (fin >>x >> y >> w)
    {
        adj.emplace_back(w, std::make_pair(x, y));
    }

    id.resize(n);
    std::iota(id.begin(), id.end(), 0);


    stable_sort(adj.begin(), adj.end());

    int parent1, parent2;
    std::vector<int> sz(n, 1);

    for (const auto &edge : adj) {
        short src = edge.second.first;
        short dest = edge.second.second;
        if (root(src) != root(dest)) {
            mst += edge.first;

            if (src == dest)
                continue;

            parent1 = root(src);
            parent2 = root(dest);

            if (parent1 == parent2)
                continue;

            if (sz[parent1] < sz[parent2])
                std::swap(parent1, parent2);

            id[parent2] = parent1;
            sz[parent1] += sz[parent2];

        }
    }

    fout << mst;

    fin.close();
    fout.close();
    return 0;
}