#include<bits/stdc++.h>
using namespace std;
using namespace std;

#define MAX_V 10000
#define INF 1e9
typedef pair<int, int> pii;

struct edge{
    int to, cost;
};

int V;
bool used[MAX_V];
vector<edge> G[MAX_V];

/*
  O(E log V)
  ?????°??±?????????????????´???vector?????????????????¨???
*/
int prim()
{
    priority_queue<pii, vector<pii>, greater<pii> > Q;
    Q.push(pii(0, 0));
    memset(used, false, sizeof(used));
    int res = 0;
  
    while (!Q.empty()) {
	pii p = Q.top(); Q.pop();
	int v = p.second;
	if (used[v]) continue;
	used[v] = true;
	res += p.first;
	for (int i = 0; i < (int)G[v].size(); i++) {
	    edge e = G[v][i];
	    Q.push(pii(e.cost, e.to));
	}
    }
    return res;
}

int main()
{
    int E,s,t,w;
    cin >> V >> E;
    for (int i = 0; i < E; i++) {
	cin >> s >> t >> w;
	G[s].push_back((edge){t, w});
	G[t].push_back((edge){s, w});
    }
    cout << prim() << endl;
    return 0;
}