#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;


const int MAX_V = 10000;
const int MAX_E = 100000;
int finde[MAX_V];

struct Edge {
	int first;
	int second;
	int weight;
};
vector<Edge> e;

bool operator < (const Edge& a, const Edge& b) {
	return a.weight < b.weight;
}

bool Judge(int m, int n) {
	while (finde[m] != m) m = finde[m];
	while (finde[n] != n) n = finde[n];
	if (m == n) {
		return false;
	}
	 finde[n]= m;
	return true;
}

int min_span_tree(int n, int m) {

	for (int i = 0; i < m; i++) finde[i] = i;
	int count = 0;
	int ret = 0;
	int f, s;
	for (int i = 0;count<m-1; i++) {
		f = e[i].first;
		s = e[i].second;
		if (Judge(f,s)) {		
			ret += e[i].weight;
			count++;
		}
	}
	return ret;
}
int main() {
	int n, m;
	cin >> m >> n;
	for (int i = 0; i < n; i++) {
		int s, t, w;
		cin>>s>>t>>w;
		e.push_back(Edge{ s, t, w });
	}
	sort(e.begin(), e.end());
	int ret = min_span_tree(n, m);
	cout << ret << endl;
	return 0;
}