#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>

#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define __PAUSE system("pause");
#define vec std::vector <
#define in std::cin
#define out std::cout

typedef long long ll;

constexpr ll INF = 1000000000;


int main() {

  ll n, m;
  in >> n >> m;

  vec vec ll >> g(n, vec ll > (n, INF));
  for (ll i = 0; i < m; i++) {
    ll tmp1 = 0, tmp2 = 0, tmp3 = 0;
    in >> tmp1 >> tmp2 >> tmp3;
    g[tmp1 - 1][tmp2 - 1] = tmp3;
    g[tmp2 - 1][tmp1 - 1] = tmp3;
  }

  vec bool> used(n);
  vec ll> min_e(n, INF), sel_e(n, -1);
  min_e[0] = 0;
  ll ans = 0;
  for (ll i = 0; i < n; ++i) {
    int v = -1;
    for (ll j = 0; j < n; ++j)
      if (!used[j] && (v == -1 || min_e[j] < min_e[v])) v = j;
    if (min_e[v] == INF) {
      return 0;
    }

    used[v] = true;
    if (sel_e[v] != -1){
      ans += g[v][sel_e[v]];
      //out << v << " " << sel_e[v] << "\n";
    }
    for (ll to = 0; to < n; ++to)
      if (g[v][to] < min_e[to]) {
        min_e[to] = g[v][to];
        sel_e[to] = v;
      }
  }
  out << ans;
  __PAUSE
}