#include <bits/stdc++.h>

using namespace std;

#define MAX_V 10000
#define INF 1e9
typedef pair<int,int> pii;

struct edge{
  int to,cost;
};

int V;
bool used[MAX_V];
vector<edge> G[MAX_V];

int prim(){
  priority_queue<pii,vector<pii>,greater<pii> > Q;
  Q.push(pii(0,0));
  memset(used,false,sizeof(used));
  int res = 0;
  
  while(!Q.empty()){
    pii p = Q.top(); Q.pop();
    int v = p.second;
    if(used[v]){ continue; }
    used[v] = true;
    res += p.first;
    for(int i = 0 ; i < (int)G[v].size() ; i++){
      edge e = G[v][i];
      Q.push(pii(e.cost,e.to));
    }
  }
  return res;
}

int main(){
  int E,s,t,w;
  cin >> V >> E;
  for(int i = 0 ; i < E ; i++){
    cin >> s >> t >> w;
    G[s].push_back((edge){t,w});
    G[t].push_back((edge){s,w});
  }
  cout << prim() << endl;
  return 0;
}