#include <bits/stdc++.h>
using namespace std;
#include <atcoder/dsu>

int main() {
  int n, m;
  cin >> n >> m;
  vector<tuple<long long, int, int>> edges;
  for (int i = 0; i < m; i++) {
    int a, b, w;
    cin >> a >> b >> w;
    a--, b--;
    edges.push_back({w, a, b});
  }
  sort(begin(edges), end(edges));
  atcoder::dsu uf(n);
  long long ans = 0;
  for (auto [w, a, b] : edges) {
    if (uf.same(a, b)) continue;
    ans += w * uf.size(a) * uf.size(b);
    uf.merge(a, b);
  }
  cout << ans << "\n";
}