// Slower C++ solution:
#include <bits/stdc++.h>

#define EPS 1e-9

#define INF 1070000000LL

#define MOD 1000000007LL

#define fir first

#define foreach(it,X) for(auto it=(X).begin();it!=(X).end();it++)

#define numa(x,a) for(auto x: a)

#define ite iterator

#define mp make_pair

#define mt make_tuple

#define rep(i,n) rep2(i,0,n)

#define rep2(i,m,n) for(int i=m;i<(n);i++)

#define pb push_back

#define pf push_front

#define sec second

#define sz(x) ((int)(x).size())

#define ALL( c ) (c).begin(), (c).end()

#define loop(n) for(int xxxxxxxx = 0; xxxxxxxx < (n) ; xxxxxxxx++)

#define gcd(a,b) __gcd(a,b)

#define endl "\n"

using namespace std;

template <int POS, class TUPLE> void deploy(std::ostream &os, const TUPLE &tuple){}

template <int POS, class TUPLE, class H, class ...Ts> void deploy(std::ostream &os, const TUPLE &t){ os << (POS == 0 ? "" : ", ") << get<POS>(t); deploy<POS + 1, TUPLE, Ts...>(os, t); }

template <class ...Ts> std::ostream& operator<<(std::ostream &os, const std::tuple<Ts...> &t){ os << "("; deploy<0, std::tuple<Ts...>, Ts...>(os, t); os << ")"; return os; }

template <class T> std::ostream& operator<<(std::ostream &os, std::vector<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }

template <class T> std::ostream& operator<<(std::ostream &os, std::set<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }

template <class T> std::ostream& operator<<(std::ostream &os, std::queue<T> q){ os << "{"; for(; !q.empty(); q.pop()){ os << q.front() << (q.size() != 1 ? ", " : "}"); } return os; }

template <class T> std::ostream& operator<<(std::ostream &os, std::priority_queue<T> q){ os << "{"; for(; !q.empty(); q.pop()){ os << q.top() << (q.size() != 1 ? ", " : "}"); } return os; }

template <class T, class K> std::ostream& operator<<(std::ostream &os, std::map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "}" : ", "); return os; }

template <class T, class K> std::ostream& operator<<(std::ostream &os, std::unordered_map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "}" : ", "); return os; }

#define DEBUG1(var0) { std::cerr << (#var0) << "=" << (var0) << endl; }

#define DEBUG2(var0, var1) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG1(var1); }

#define DEBUG3(var0, var1, var2) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG2(var1,var2); }

#define DEBUG4(var0, var1, var2, var3) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG3(var1,var2,var3); }

#define DEBUG5(var0, var1, var2, var3, var4) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG4(var1,var2,var3,var4); }

#define DEBUG6(var0, var1, var2, var3, var4, var5) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG5(var1,var2,var3,var4,var5);}



typedef istringstream iss;

typedef long long ll;

typedef pair<ll,ll> pi;

typedef stringstream sst;

typedef vector<ll> vi;

#define MAX_V 10100

vector <pair <int,ll> > edge[MAX_V];//edgeのコスト

bool used[MAX_V];//頂点iがxに含まれているかどうか

int V,E;

ll res;

void Prim(){

  memset(used,0,sizeof(used));

  priority_queue<pair <ll,int> , vector <pair <ll,int> >, greater<pair <ll,int> > > que;

  //集合Xに0を入れる

  que.push(mp(0,0));

  res = 0;

  while(!que.empty()){

    pair <ll,int> now_v = que.top();

    que.pop();

    if(!used[now_v.sec]){

      res += now_v.fir;

      used[now_v.sec] = true;

    }else{

      continue;

    }

    rep(i,sz(edge[now_v.sec])){

      if(!used[edge[now_v.sec][i].fir]){

        que.push(mp(edge[now_v.sec][i].sec,edge[now_v.sec][i].fir));

      }

    }

  }

}

int main(){

  cin.tie(0);

  ios_base::sync_with_stdio(0);

  cin >> V >> E;

  rep(i,E){

    int x,y;

    ll z;

    cin >> x >> y >> z;

    edge[x].pb(mp(y,z));

    edge[y].pb(mp(x,z));

  }

  Prim();

  cout << res << endl;

  

  return 0;

}

// Faster C++ solution for the same problem (measured speedup: 1.268314176160066x):
#include <bits/stdc++.h>

#define EPS 1e-9

#define INF 1070000000LL

#define MOD 1000000007LL

#define fir first

#define foreach(it,X) for(auto it=(X).begin();it!=(X).end();it++)

#define numa(x,a) for(auto x: a)

#define ite iterator

#define mp make_pair

#define mt make_tuple

#define rep(i,n) rep2(i,0,n)

#define rep2(i,m,n) for(int i=m;i<(n);i++)

#define pb push_back

#define pf push_front

#define sec second

#define sz(x) ((int)(x).size())

#define ALL( c ) (c).begin(), (c).end()

#define loop(n) for(int xxxxxxxx = 0; xxxxxxxx < (n) ; xxxxxxxx++)

#define gcd(a,b) __gcd(a,b)

#define endl "\n"

using namespace std;

template <int POS, class TUPLE> void deploy(std::ostream &os, const TUPLE &tuple){}

template <int POS, class TUPLE, class H, class ...Ts> void deploy(std::ostream &os, const TUPLE &t){ os << (POS == 0 ? "" : ", ") << get<POS>(t); deploy<POS + 1, TUPLE, Ts...>(os, t); }

template <class ...Ts> std::ostream& operator<<(std::ostream &os, const std::tuple<Ts...> &t){ os << "("; deploy<0, std::tuple<Ts...>, Ts...>(os, t); os << ")"; return os; }

template <class T> std::ostream& operator<<(std::ostream &os, std::vector<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }

template <class T> std::ostream& operator<<(std::ostream &os, std::set<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }

template <class T> std::ostream& operator<<(std::ostream &os, std::queue<T> q){ os << "{"; for(; !q.empty(); q.pop()){ os << q.front() << (q.size() != 1 ? ", " : "}"); } return os; }

template <class T> std::ostream& operator<<(std::ostream &os, std::priority_queue<T> q){ os << "{"; for(; !q.empty(); q.pop()){ os << q.top() << (q.size() != 1 ? ", " : "}"); } return os; }

template <class T, class K> std::ostream& operator<<(std::ostream &os, std::map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "}" : ", "); return os; }

template <class T, class K> std::ostream& operator<<(std::ostream &os, std::unordered_map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "}" : ", "); return os; }

#define DEBUG1(var0) { std::cerr << (#var0) << "=" << (var0) << endl; }

#define DEBUG2(var0, var1) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG1(var1); }

#define DEBUG3(var0, var1, var2) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG2(var1,var2); }

#define DEBUG4(var0, var1, var2, var3) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG3(var1,var2,var3); }

#define DEBUG5(var0, var1, var2, var3, var4) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG4(var1,var2,var3,var4); }

#define DEBUG6(var0, var1, var2, var3, var4, var5) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG5(var1,var2,var3,var4,var5);}



typedef istringstream iss;

typedef long long ll;

typedef pair<ll,ll> pi;

typedef stringstream sst;

typedef vector<ll> vi;

#define MAX_V 10100



int par[MAX_V];

int myrank[MAX_V];



void init(int n){//要素初期化

  rep(i,n){

    par[i] = i;

    myrank[i] = 0;

  }

}



int find(int x){//木の根を求める

  if(par[x] == x){

    return x;

  }else{

    return par[x] = find(par[x]);

  }

}



void unite(int x,int y){//xとyの属する集合を併合

  x = find(x);

  y = find(y);

  if(x == y){

    return;

  }

  if(myrank[x] < myrank[y]){

    par[x] = y;

  }else{

    par[y] = x;

    if(myrank[x] == myrank[y]){

      myrank[x] += 1;

    }

  }

 

}



bool same(int x,int y){//x,yが同じ集合に属するか否か

  return find(x) == find(y);

}



//Union-find木終わり



vector <pair <pair <int,int>, ll> > edge;

int V,E;

bool comp(const pair <pair <int,int> , ll> &e1, const pair <pair <int,int>, ll> &e2){

  return e1.sec < e2.sec;

}



ll Kruscal(){

  sort(ALL(edge),comp);

  init(V+10);

  ll res = 0;

  rep(i,sz(edge)){

    pair <pair <int,int>,ll> now = edge[i];

    if(!same(now.fir.fir,now.fir.sec)){

      unite(now.fir.fir,now.fir.sec);

      res += now.sec;

    }

  }

  return res;

}



int main(){

  cin.tie(0);

  ios_base::sync_with_stdio(0);

  cin >> V >> E;

  rep(i,E){

    int x,y;

    ll z;

    cin >> x >> y >> z;

    edge.pb(mp(mp(x,y),z));

  }

  cout << Kruscal() << endl;

  return 0;

}