#include <bits/stdc++.h>
#define rep(i,n) for (int i = (0); i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define limit(x,l,r) max(l,min(x,r))
#define lims(x,l,r) (x = max(l,min(x,r)))
#define isin(x,l,r) ((l) <= (x) && (x) < (r))
#define show(x) cout << #x << " = " << (x) << endl
#define show2(x,y) cout << #x << " = " << (x) << ", " << #y << " = " << (y) << endl
#define show3(x,y,z) cout << #x << " = " << (x) << ", " << #y << " = " << (y) <<  ", " << #z << " = " << (z) << endl
#define showv(v) rep(i,v.size()) printf("%d%c", v[i], i==v.size()-1?'\n':' ')
#define showv2(v) rep(j,v.size()) showv(v[j])
#define showt(t,n) rep(i,n) printf("%d%c", t[i], i==n-1?'\n':' ')
#define showt2(t,r,c) rep(j,r) showt(t[j],c)
#define showvp(p) rep(i,p.size()) printf("%d %d\n", p[i].first, p[i].second)
#define printv(v) rep(i,v.size()) printf("%d\n", v[i])
#define printt(t,n) rep(i,n) printf("%d\n", t[i])
#define incl(v,x) (find(all(v),x)!=v.end())
#define incls(s,c) (s.find(c)!=string::npos)
#define lb(a,x) distance((a).begin(),lower_bound(all(a),(x)))
#define ub(a,x) distance((a).begin(),upper_bound(all(a),(x)))
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define bit(n,k) ((n>>k)&1) // nのk bit目
#define bn(x) ((1<<x)-1)
#define dup(x,y) (((x)+(y)-1)/(y))
#define newline puts("")
#define uni(x) x.erase(unique(all(x)),x.end())
#define SP << " " <<
using namespace std;
using ll = long long;
using ld = long double;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vc = vector<char>;
using vvc = vector<vc>;
using vs = vector<string>;
using vb = vector<bool>;
using vvb = vector<vb>;
using P = pair<int, int>;
using T = tuple<int, int, int>;
using vp = vector<P>;
using vt = vector<T>;
const int mod = 1000000007;
const double EPS = 1e-9;
//const long double EPS = 1e-14;
const int INF = (1<<30)-1;
const ll LINF = (1LL<<62)-1;
#define dame { puts("No"); return 0;}
#define yn {puts("Yes");}else{puts("No");}
inline int in() { int x; cin >> x; return x;}
inline ll lin() { ll x; cin >> x; return x;}
inline char chin() { char x; cin >> x; return x;}
inline string stin() { string x; cin >> x; return x;}
inline double din() { double x; cin >> x; return x;}
//template<class T = int> inline T in() { T x; cin >> x; return (x);}
template<typename T>inline ll suma(const vector<T>& a) { ll res(0); for (auto&& x : a) res += x; return res;}
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
char itoa(int n) { return n + '0';}
ll gcd(ll a, ll b) { return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) { return a/gcd(a,b)*b;}
const int dx[4] = {1, 0,-1, 0};
const int dy[4] = {0, 1, 0,-1};

const int MAX_V = 10005;
int mincost[MAX_V]; // 頂点Xからの辺の最小コスト
bool used[MAX_V]; // 頂点iがXに含まれているか
int V; // 頂点数
int E; // 辺の本数
struct edge { int to, cost; };
vector<edge> g[MAX_V];

// プリム法: 最小全域木のコストの合計値を返す O(|E|log|V|)

int prim() {
  priority_queue<P, vector<P>, greater<P>> pq;
  for (int i = 0; i < V; ++i) {
    mincost[i] = INF;
    used[i] = false;
  }
  mincost[0] = 0;
  pq.push(P(0,0));
  int res = 0;
  while (!pq.empty()) {
    P p = pq.top(); pq.pop();
    int v = p.second;
    if (used[v]) continue;
    used[v] = 1;
    res += p.first;
    for (edge e : g[v]) {
      pq.push(P(e.cost, e.to));
    }
  }
  return res;
}

int main () {
  cin >> V >> E;
  rep(i,E) {
    int s, t, w;
    cin >> s >> t >> w;
    g[s].pb({t,w});
    g[t].pb({s,w});
  }
  cout << prim() << endl;
  return 0;
}


Measured memory_bytes: 7968