#include <bits/stdc++.h>
#define ALL(x) (x).begin(), (x).end()
#define LB(v, x) (int)(lower_bound(ALL(v), x) - (v).begin())
#define UQ(v) sort(ALL(v)), (v).erase(unique(ALL(v)), (v).end())
#define IO ios::sync_with_stdio(false), cin.tie(nullptr);
#define chmax(a, b) (a) = (a) < (b) ? (b) : (a)
#define chmin(a, b) (a) = (a) < (b) ? (a) : (b)
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

struct DSU {
    DSU() = default;
    DSU(int n) {
        par.resize(n);
        iota(par.begin(), par.end(), 0);
        sz.assign(n, 1);
        forest_count = n;
    }

    int find(int x) {
        if (par[x] == x) return x;
        return par[x] = find(par[x]);
    }
    bool merge(int x, int y) {
        x = find(x), y = find(y);
        if (x == y) return false;
        if (sz[x] < sz[y]) swap(x, y);
        par[y] = x;
        sz[x] += sz[y];
        forest_count--;
        return true;
    }
    int size(int x) { return sz[find(x)]; }
    bool same(int x, int y) { return find(x) == find(y); }
    int count() { return forest_count; }
    vector<vector<int>> groups() {
        int n = par.size();
        vector<vector<int>> ret(n);
        for (int i = 0; i < n; i++) ret[find(i)].push_back(i);
        ret.erase(remove_if(ret.begin(), ret.end(), [&](const vector<int>& v) { return v.empty(); }), ret.end());
        return ret;
    }

private:
    vector<int> par, sz;
    int forest_count;
};

int main() {
    int N, M;
    cin >> N >> M;
    vector<tuple<ll, int, int>> E(M);
    for (auto& [w, u, v] : E) cin >> u >> v >> w, u--, v--;
    sort(ALL(E));
    reverse(ALL(E));

    ll ans = 0;
    DSU dsu(N);
    for (auto [w, u, v] : E) {
        if (dsu.merge(u, v)) ans += w;
    }

    cout << ans * 2 << endl;
}