#include <algorithm>
#include <fstream>
#include <iostream>
#include <vector>

std::fstream fin("doc/grafpond.in");

// The struct data type
struct Path {
  int fst;  // First node
  int scn;  // Second node
  int cost; // The cost of the path
};

int n, m, sum;
std::vector<Path> L;
std::vector<int> F;
std::vector<int> MST;

void MakeList(const int m) {
  for (int i = 0; i < m; i++) {
    // Reading the two nodes and the cost of a path
    int x, y, c;
    fin >> x >> y >> c;

    L[i].fst = x;
    L[i].scn = y;
    L[i].cost = c;
  }
}

// Sorting function for sort()
bool Sorting(const Path a, const Path b) { return a.cost < b.cost; }

void Initializing() {
  for (int i = 0; i < n; i++) {
    F[i] = i;
  }
}

int FindK(int x) {
  int r = x;
  while (r != F[r]) {
    r = F[r];
  }

  int y = x;
  while (y != r) {
    int t = F[y];
    F[y] = r;
    y = t;
  }
  return r;
}

int UnionK(int sum, int i) {
  int x, y;
  x = FindK(L[i].fst);
  y = FindK(L[i].scn);

  if (x != y) {
    F[x] = y;
    MST.push_back(i);
    sum += L[i].cost;
  }
  return sum;
}

int main(int argc, char *argv[]) {
  // Test if the file has succesfully open
  if (!fin.is_open()) {
    std::cout << "Error: Failed to open file." << std::endl;
    exit(1);
  }

  // Reading the number of nodes and paths
  fin >> n >> m;
  L.resize(m);
  MST.resize(m);
  F.resize(n);

  // Making the path list and sorting it
  MakeList(m);
  std::sort(L.begin(), L.end(), Sorting);

  // Intializing the father vector
  Initializing();

  for (int i = 0; i < m; i++) {
    sum = UnionK(sum, i);
  }

  std::cout << sum;
  return 0;
}