#include <iostream>
#include "vector"
#include "set"
using namespace std;
int main() {
    long long n, m;
    cin >> n >> m;
    vector<vector<pair<long long,long long>>> list(n);
    set<pair<long long,long long>> edges;
    long long from, to, cost;
    for (long long i = 0; i < m; ++i) {
        cin >> from >> to >> cost;
        list[from-1].push_back(make_pair(cost, to-1));
        list[to-1].push_back(make_pair(cost, from-1));
    }

    long long res = 0, counter = -1, v;
    vector<bool> used(n, false);
    edges.insert(make_pair(0, list.front().front().second));

    for (long long i = 0; i < n; ++i) {
        if (counter==n-1) break;
        v = edges.begin()->second;
        cost = edges.begin()->first;
        if(used[v]) continue;
        used[v] = true;
        res+=cost;
        counter++;
        edges.erase(edges.begin());
        for (long long j = 0; j < list[v].size(); ++j) {
            if(!used[list[i][j].second]) edges.insert(list[i][j]);
        }
    }

    cout << res;

    return 0;
}