#include <iostream>
#include <vector>

using namespace std;

struct Edge {
	int weight;
	int from;
	int to;
};

class CGraph {
public:
	CGraph(int size) : rank(size, 0), cheapest(size, -1), size(size) {
		parent.resize(size);
		for (int i = 0; i < size; ++i) {
			parent[i] = i;
		}
		components_num = size;
	};
	~CGraph() {};
	void add(Edge temp) {
		edges.push_back(temp);
	}
	int find_root(int vertex) {
		if (parent[vertex] == vertex) {
			return vertex;
		}
		return parent[vertex] = find_root(parent[vertex]);
	}
	void union_set(int a, int b) {
		a = find_root(a);
		b = find_root(b);
		if (a != b) {
			if (rank[a] < rank[b]) {
				swap(a, b);
			}
			parent[b] = a;
			if (rank[a] == rank[b]) {
				++rank[a];
			}
		}
	}

	int count_mst_weight() {
		while (components_num > 1) {
			for (int i = 0; i < edges.size(); ++i) {
				int pupa = find_root(edges[i].from);
				int lupa = find_root(edges[i].to);

				if (pupa != lupa) { //вроде это должно работать но сэмпл выдает 5
					if (cheapest[pupa] == -1 || (edges[cheapest[pupa]].weight >= edges[i].weight && edges[cheapest[pupa]].to < cheapest[pupa])) {
						cheapest[pupa] = i;
					}
					if (cheapest[lupa] == -1 || (edges[cheapest[lupa]].weight >= edges[i].weight && edges[cheapest[lupa]].to < cheapest[lupa])) {
						cheapest[lupa] = i;
					}
				}
			}
			for (int i = 0; i < size; ++i) {
				if (cheapest[i] != -1) {
					int pupa = find_root(edges[cheapest[i]].from);
					int lupa = find_root(edges[cheapest[i]].to);
					if (pupa != lupa) {
						mst_weight += edges[cheapest[i]].weight;
						union_set(pupa, lupa);
						--components_num;
					}
				}
			}
		}
		return mst_weight;
	}


private:
	vector<int> cheapest;
	vector<Edge> edges;
	vector<int> parent;
	vector<int> rank;
	int components_num;
	int size;
	int mst_weight = 0;
};

int main() {
	int n, m;
	cin >> n >> m;
	CGraph graph(n);
	for (int i = 0; i < m; ++i) {
		Edge temp;
		cin >> temp.from >> temp.to >> temp.weight;
		--temp.from;
		--temp.to;

		graph.add(temp);
	}
	cout << graph.count_mst_weight();
	system("pause");

	return 0;
}