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

struct edge
{
	int s, e, w;
};

bool operator<(const edge& a, const edge& b)
{
	return a.w < b.w;
}

const int N = (int)1e5 + 100;

int p[N];
int sz[N];

int find_set(int v)
{
	if(p[v] == v)
		return v;

	return p[v] = find_set(p[v]);
}

int merge(int a, int b)
{
	a = find_set(a);
	b = find_set(b);

	if(a == b)
		return 0;

	if(sz[a] < sz[b])
		swap(a, b);

	sz[a] += sz[b];
	p[b] = a;

	return 1;
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	int nv, ne;
	cin >> nv >> ne;

	vector<edge> edges(ne);

	for(int i = 0; i < ne; i++)
	{
		cin >> edges[i].s >> edges[i].e >> edges[i].w;

		--edges[i].s;
		--edges[i].e;
	}

	for(int i = 0; i < nv; i++)
	{
		p[i] = i;
		sz[i] = 1;
	}

	long long res = 0;
	sort(edges.begin(), edges.end());

	for(int i = 0; i < ne; i++)
	{
		if(merge(edges[i].s, edges[i].e))
		{
			res += edges[i].w;
		}
	}

	cout << res;
}