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

struct dsu {
    dsu(int n) : p(n, -1) {}
    int leader(int u) { return p[u] < 0 ? u : leader(p[u]); }
    bool same(int u, int v) { return leader(u) == leader(v); }
    void merge(int u, int v) {
        u = leader(u);
        v = leader(v);
        if (u == v) return;
        if (p[u] > p[v]) swap(u, v);
        p[u] += p[v];
        p[v] = u;
    }
    int size(int u) { return -p[leader(u)]; }
    vector<vector<int>> groups() {
        int n = p.size();
        vector<vector<int>> V(n);
        for (int i = 0; i < n; i++) {
            V[leader(i)].push_back(i);
        }
        vector<vector<int>> res;
        for (auto v : V) {
            if (v.size()) res.push_back(v);
        }
        return res;
    }
private:
    vector<int> p;
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N, M;
    cin >> N >> M;
    vector<tuple<int, int, int>> E(M);
    for (int i = 0, u, v, w; i < M; i++) {
        cin >> u >> v >> w;
        u--, v--;
        E[i] = {w, u, v};
    }
    sort(E.begin(), E.end());
    reverse(E.begin(), E.end());
    dsu uf(N);
    long long ans = 0;
    for (auto t : E) {
    	int u = get<1>(t);
    	int v = get<2>(t);
    	int w = get<0>(t);
        if (uf.same(u, v)) continue;
        uf.merge(u, v);
        ans += w;
    }
    cout << 2 * ans << endl;
}