// includes
#include <bits/stdc++.h>

// macros
#define ll long long int
#define pb emplace_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(st, itr) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define vrep(v, i) for(int i = 0; i < (v).size(); i++)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define FI first
#define SE second
#define dump(a, n) for(int i = 0; i < n; i++)cout << a[i] << "\n "[i + 1 != n];
#define dump2(a, n, m) for(int i = 0; i < n; i++)for(int j = 0; j < m; j++)cout << a[i][j] << "\n "[j + 1 != m];
using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
typedef pair<double, double> Pd;
typedef complex<double> cd;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1e9 + 7;

// solve
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << p.first << " " << p.second; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}

typedef struct UnionFind_ {
  vector<int> par;
  vector<int> rank_;
  UnionFind_(int n): rank_(n, 0) {
    for(int i = 0; i < n; i++)par.push_back(i);
  }
  int find(int x) {
    if(par[x] == x)return x;
    else return par[x] = find(par[x]);
  }
  bool same(int x, int y) {
    if(find(x) == find(y))return true;
    else return false;
  }
  bool unite(int x, int y){
    int xp = find(x);
    int yp = find(y);
    if(xp == yp)return false;
    if(rank_[xp] > rank_[yp])par[yp] = xp;
    else if(rank_[xp] < rank_[yp])par[xp] = yp;
    else {
      par[yp] = xp;
      rank_[xp]++;
    }
    return true;
  }
} UnionFind;

template <typename T>
struct Graph{
  struct edge{
    int to;
    T cost;
    edge(int to, T cost): to(to), cost(cost){}
  };
  int n;
  vector<vector<edge>> edges;
  Graph(int n): n(n){ edges.resize(n);
  }
  void adde(int from, int to, T cost){
    edges[from].push_back(edge(to, cost));
    edges[to].push_back(edge(from, cost));
  }
  T boruvka(){
    T ans = 0;
    vector<vector<edge>> res(n);
    UnionFind uf(n);

    while(true){
      vector<pair<int, edge>> f;
      int c = 0;
      vector<int> id(n, -1);
      for(int i = 0; i < n; i++){
        if(id[i] == -1){
          id[i] = c;
          vector<int> C;
          queue<int> q;
          q.push(i);
          while(!q.empty()){
            int v = q.front(); q.pop();
            C.push_back(v);
            for(auto e: res[v]){
              if(id[e.to] == -1){
                id[e.to] = c;
                q.push(e.to);
              }
            }
          }
          c++;
          int from = -1, to = -1;
          T cost = -1;
          for(int j = 0; j < C.size(); j++){
            int v = C[j];
            for(auto e: edges[v]){
              if(id[e.to] != id[i]){
                if(cost == -1 || cost > e.cost){
                  cost = e.cost;
                  to = e.to;
                  from = v;
                }
              }
            }
          }
          if(cost != -1)f.push_back(make_pair(from, edge(to, cost)));
        }
      }
      if(c == 1)break;
      for(int i = 0; i < f.size(); i++){
        int u = f[i].first;
        int v = f[i].second.to;
        T cost = f[i].second.cost;
        if(!uf.same(u, v)){
          uf.unite(u, v);
          ans += cost;
          res[u].push_back(edge(v, cost));
          res[v].push_back(edge(u, cost));
        }
      }
    }
    return ans;
  }
};

using GraphI = Graph<int>;
using GraphL = Graph<long long>;

int main(int argc, char const* argv[])
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  GraphL graph(n);
  rep(i, m){
    int s, t;
    ll w;
    cin >> s >> t >> w;
    graph.adde(s, t, w);
  }
  cout << graph.boruvka() << endl;
  return 0;
}



Measured memory_bytes: 9300