#include <bits/stdc++.h>
#define endl '\n'
#define int long long
#define lint long long
#define pii pair<int, int>
#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define FORR(i, a, b) for(int i = (a); i > (b); --i)
#define REP(i, n) FOR(i, 0, n)
#define SZ(v) ((int)v.size())
#define ZERO(a) memset(a, 0, sizeof(a))
#define MINUS(a) memset(a, 0xff, sizeof(a))
#define FINF(a) memset(a, 0x3f, sizeof(a))
#define POW(n) (1LL << (n))
#define POPCNT(n) (__builtin_popcount(n))
#define IN(i, a, b) ((a) <= (i) && (i) <= (b))
using namespace std;
template <typename T> inline bool CHMIN(T& a,T b) { if(a > b) { a = b; return 1; } return 0; }
template <typename T> inline bool CHMAX(T& a,T b) { if(a < b) { a = b; return 1; } return 0; }
template <typename T> inline void SORT(T& a) { sort(begin(a), end(a)); }
template <typename T> inline void REV(T& a) { reverse(begin(a), end(a)); }
template <typename T> inline void UNI(T& a) { sort(a.begin(), a.end()); a.erase(unique(a.begin(), a.end()), a.end()); }
template <typename S, typename T> inline T LB(S& v, T a) { return *lower_bound(begin(v), end(v), a); }
template <typename S, typename T> inline int LBP(S& v, T a) { return lower_bound(begin(v), end(v), a) - begin(v); }
template <typename S, typename T> inline T UB(S& v, T a) { return *upper_bound(begin(v), end(v), a); }
template <typename S, typename T> inline int UBP(S& v, T a) { return upper_bound(begin(v), end(v), a) - begin(v); }
template <typename S, typename T> ostream& operator << (ostream& os, const pair<S, T>& p) { os << p.first << " " << p.second; return os; }
template <typename S, typename T> istream& operator >> (istream& is, pair<S, T>& p) { is >> p.first >> p.second; return is; }
template <typename T> ostream& operator << (ostream& os, const vector<T>& v) { for (int i = 0; i < v.size(); ++i) { if (i) os << " "; os << v[i]; } return os; }
template <typename T> istream& operator >> (istream& is, vector<T>& v) { for(T& in : v) is >> in; return is; }
template <typename T = int> vector<T> make_v(size_t a) { return vector<T>(a); }
template <typename T, typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...)); }
template <typename T, typename V> typename enable_if<is_class<T>::value == 0>::type fill_v(T &t, const V &v) { t = v; }
template <typename T, typename V> typename enable_if<is_class<T>::value != 0>::type fill_v(T &t, const V &v) { for(auto &e : t) fill_v(e, v); }
const lint MOD = 1000000007;
const lint INF = 0x3f3f3f3f3f3f3f3f;
const double PI = 3.14159265358979323846;
const double EPS = 1e-10;

template <typename T> struct Edge {
    int to;
    T cost;
    Edge() {}
    Edge(int t, T c) : to(t), cost(c) {}
    bool operator < (const Edge& e) const {
        return (to != e.to ? to < e.to : cost < e.cost);
    }
};

template <typename T> class Prim {
    void build() {
        using P = tuple<T, int, int>;
        tree.resize(g.size());
        cost = 0;
        vector<bool> vis(g.size(), false);
        vector<set<Edge<T>>> eused(g.size());
        priority_queue<P, vector<P>, greater<P>> que;
        que.emplace(0, -1, 0);
        while (!que.empty()) {
            T c, f, t;
            tie(c, f, t) = que.top();
            que.pop();
            if (vis[t]) continue;
            vis[t] = true;
            cost += c;
            if (~f) {
                tree[f].emplace_back(t, c);
                tree[t].emplace_back(f, c);
                eused[f].emplace(t, c);
                eused[t].emplace(f, c);
            }
            for (auto& e : g[t]) {
                que.emplace(e.cost, t, e.to);
            }
        }
        used.resize(g.size());
        for (int i = 0; i < g.size(); ++i) {
            used[i].resize(g[i].size(), false);
            for (int j = 0; j < g[i].size(); ++j) {
                used[i][j] = eused[i].count(g[i][j]);
            }
        }
    }

public:
    using UndirectedGraph = vector<vector<Edge<T>>>;
    const UndirectedGraph& g;
    UndirectedGraph tree;  // 最小全域木
    T cost;                // 最小全域木のコスト
    vector<vector<bool>> used;

    Prim(const UndirectedGraph& g) : g(g), used(g.size()) { build(); }
};

int V, E;
vector<vector<Edge<int>>> g;

void _main() {
    cin >> V >> E;
    g.resize(V);
    REP (i, E) {
        int s, t, w;
        cin >> s >> t >> w;
        g[s].emplace_back(t, w);
        g[t].emplace_back(s, w);
    }
    Prim<int> p(g);
    cout << p.cost << endl;
}

signed main(signed argc, char **argv) {
    if (argc > 1) {
        if (strchr(argv[1], 'i')) freopen("input.txt", "r", stdin);
        if (strchr(argv[1], 'o')) freopen("output.txt", "w", stdout);
    }
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(10);
    _main();
    return 0;
}


Measured memory_bytes: 16180