```cpp

include <bits/stdc++.h>

using namespace std;

struct DSU { vector par; DSU(int n) : par(n + 1) { for (int i = 1; i <= n; i++) par[i] = i; } int find(int x) { return par[x] == x ? x : par[x] = find(par[x]); } bool unite(int a, int b) { a = find(a), b = find(b); if (a == b) return false; par[b] = a; return true; } };

int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m; cin >> n >> m; vector<tuple<int,int,int>> edges; while (m--) { int u, v, w; cin >> u >> v >> w; edges.push_back({w, u, v}); } sort(edges.begin(), edges.end()); DSU dsu(n); long long total = 0; for (auto& [w, u, v] : edges) if (dsu.unite(u, v)) total += w; cout << total << '\n'; return 0; }