// C++ 14
#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <algorithm>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <math.h>

#define ll long long
#define Int int
#define loop(__x, __start, __end) for(Int __x = __start; __x < __end; __x++)
#define loopdown(__x, __start, __end) for(Int __x = __start; __x > __end; __x--)
#define rep(__n) for(Int __x = 0; __x < __n; __x++)
#define span(__a,__x,__y) __a.begin()+__x,__a.begin()+__y
#define span_all(__a) __a.begin(),__a.end()
#define len(__x) (__x.size())
#define last(__x) (__x[__x.size()-1])

using namespace std;

struct Point {
  Int x, y;
  Point(Int x, Int y): x(x), y(y) {}
  Point(): x(0), y(0) {}

  bool operator< (const Point &p1) {
    return x < p1.x && y < p1.y;
  }
};
ostream & operator << (ostream & out, Point const & v) {
  out << "Point(" << v.x << ", " << v.y << ')';
  return out;
}

istream & operator >> (istream & in, Point & v) {
  Int x, y;
  in >> x; in >> y; v.x = x; v.y = y;
  return in;
}

// Geometry

#define EPS 0.0000000001

class Vector2 {
public:
  double x, y;
  
  Vector2(double x = 0, double y = 0): x(x), y(y) {}
  
  Vector2 operator + (Vector2 v) { return Vector2(x + v.x, y + v.y); }
  Vector2 operator - (Vector2 v) { return Vector2(x - v.x, y - v.y); }
  Vector2 operator * (double k) { return Vector2(x * k, y * k); }
  Vector2 operator / (double k) { return Vector2(x / k, y / k); }
  
  double length() { return sqrt(norm()); }
  double norm() { return x * x + y * y; }
  double dot (Vector2 v) { return x * v.x + y * v.y; }
  double cross (Vector2 v) { return x * v.y - y * v.x; }
  
  bool operator < (const Vector2 &v) const {
    return x != v.x ? x < v.x : y < v.y;
  }
  
  bool operator == (const Vector2 &v) const {
    return fabs(x - v.x) < EPS && fabs(y - v.y) < EPS;
  }
};

ostream & operator << (ostream & out, Vector2 const & v) { 
  out<< "Vector2(" << v.x << ", " << v.y << ')';
  return out;
}

istream & operator >> (istream & in, Vector2 & v) { 
  double x, y;
  in >> x;
  in >> y;
  v.x = x;
  v.y = y;
  return in;
}

struct Edge {
  Int s, t, w;
  Edge(Int s, Int t, Int w): s(s),t(t),w(w) {}
  bool operator < (const Edge &other) const {
    return w < other.w;
  }
};

#define MAX_V 10001
Int V, E;
vector<Edge> edges;

void input() {
  Int s,t,w;
  cin >> V >> E;
  rep(E) {
    cin >> s >> t >> w;
    edges.push_back(Edge(s, t, w));
  }
}


class DisjointSet {
public:
    DisjointSet(int n) {
        rank.resize(n);
        parent.resize(n);
        for (int i=0; i<n; i++) rank[i] = 0, parent[i] = i;
    }
    
    bool same(int x, int y) {
        return root(x) == root(y);
    }
    
    void unite(int x, int y) {
        x = root(x), y = root(y);
        if (rank[x] > rank[y]) {
            parent[y] = x;
        } else {
            parent[x] = y;
            if (rank[x] == rank[y]) rank[y]++;
        }
    }
    
private:
    vector<int> rank;
    vector<int> parent;
    
    int root(int x) {
        if (x != parent[x]) {
            parent[x] = root(parent[x]);
        }

        return parent[x];
    }
};

Int kruskal() {
  sort(span_all(edges));
  DisjointSet dset(V);
  Int total = 0;

  for (auto edge: edges) {
    if (dset.same(edge.s, edge.t)) continue;
    dset.unite(edge.s, edge.t);
    total += edge.w;
  }

  return total;
}

void solve() {
  cout << kruskal() << endl;
}

int main() {
  input();
  solve();
  return 0;
}



Measured memory_bytes: 4536