#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("unroll-loops")
//#pragma warning(disable : 4996)

#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcount __popcnt
#define __builtin_popcountll __popcnt64
#endif

#include <limits.h>
#include <math.h>
#include <time.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m - 1; i >= n; --i)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v, n) reverse(v, v + n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout << (x) << '\n'
#define pe(x) cout << (x) << " "
#define DEBUG(x) cout << #x << ": " << x << endl
#define lb(v, n) lower_bound(v.begin(), v.end(), (n))
#define ub(v, n) upper_bound(v.begin(), v.end(), (n))
//#define int long long
//#define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v) REP(i, v.size()) cout << v[i] << ((i == v.size() - 1) ? "\n" : " ")
template <typename T1, typename T2> inline void chmin(T1& a, T2 b) {
    if (a > b) a = b;
}
template <typename T1, typename T2> inline void chmax(T1& a, T2 b) {
    if (a < b) a = b;
}
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7;
constexpr int MAX = 500050;
const double pi = acos(-1);
constexpr double EPS = 1e-8;
constexpr ll LINF = 1e18 + 1;
constexpr int INF = 1e9 + 1;

struct UnionFind {
    int N;
    vector<int> siz;
    vector<int> par;
    vector<int> Rank;
    UnionFind(int n) : siz(n, 1), par(n), Rank(n, 0) {
        N = n;
        for (int i = 0; i < N; i++) par[i] = i;
    }
    int find(int x) {
        if (par[x] == x) {
            return x;
        } else {
            return par[x] = find(par[x]);
        }
    }
    void unite(int x, int y) {
        x = find(x);
        y = find(y);
        if (x == y) return;
        if (Rank[x] < Rank[y]) {
            par[x] = y;
            siz[x] += siz[y];
            siz[y] = siz[x];
        } else {
            siz[y] += siz[x];
            siz[x] = siz[y];
            par[y] = x;
            if (Rank[x] == Rank[y]) Rank[x]++;
        }
    }
    bool same(int x, int y) { return find(x) == find(y); }
};

struct Edge {
    int from, to, cost;
};

map<int, int> mp[200020];
void solve() {
    int N;
    cin >> N;
    int M;
    cin >> M;
    vector<Edge> es;
    REP(i, M) {
        int u, v, d;
        cin >> u >> v >> d;
        mp[u][v]++;
        mp[v][u]++;
        assert(mp[u][v] == 1 && mp[u][v] == 1);
        assert(u != v);
        // u--, v--;
        es.push_back({u, v, d});
    }
    UnionFind uf(N);
    sort(all(es), [](const Edge& a, const Edge& b) {
        if (a.cost != b.cost)
            return a.cost < b.cost;
        else if (a.from != b.from)
            return a.from < b.from;
        else
            return a.to < b.to;
    });
    ll ans = 0;
    for (auto e : es) {
        if (!uf.same(e.from, e.to)) {
            ans += e.cost;
            uf.unite(e.from, e.to);
        }
    }
    assert(uf.siz[uf.find(0)] == N);
    print(ans);
}

signed main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    solve();
}



Measured memory_bytes: 22972