#include <iostream>
#include <vector>
#include <algorithm>

struct Edge
{
    int From;
    int To;
    int Weight;
};

bool operator < (const Edge& e1, const Edge& e2) {
    return e1.Weight < e2.Weight;
}


typedef std::vector<std::vector<int>> Graph;


void MST(const std::vector<Edge>& edges, std::vector<Edge>& treeEdges, int nVertex) {
    std::vector<int> vertexId(nVertex);
    for (int i = 0; i < nVertex; ++i) {
        vertexId[i] = i;
    }
    for (int i = 0; i < edges.size(); ++i) {
        const Edge& curEdge = edges[i];
        if (vertexId[curEdge.From] != vertexId[curEdge.To]) {
            treeEdges.push_back(curEdge);
            int newId = vertexId[curEdge.From];
            int oldId = vertexId[curEdge.To];
            for (int j = 0; j < vertexId.size(); ++j) {
                if (vertexId[j] == oldId) {
                    vertexId[j] = newId;
                }
            }
        }
    }
}


int main() {
    int n = 0, m = 0;
    std::cin >> n >> m;
    Graph graph(n);
    std::vector<Edge> edges;
    for (int i = 0; i < m; ++i) {
        int from = 0, to = 0, weight = 0;
        std::cin >> from >> to >> weight;
        from -= 1;
        to -= 1;
        Edge edge;
        edge.From = from;
        edge.To = to;
        edge.Weight = weight;
        edges.push_back(edge);
    }

    std::vector<Edge> tree;
    std::sort(edges.begin(), edges.end());
    MST(edges, tree, n);
    int w = 0;
    for (const Edge& edge : tree) {
        w += edge.Weight;
    }
    std::cout << w << std::endl;
    return 0;
}