#include <bits/stdc++.h>
using namespace std;
const int maxn = 200202;
int N, M;
int pr[maxn];
int find(int v) {
    return pr[v] < 0 ? v : pr[v] = find(pr[v]);
}
int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    cin >> N >> M;
    vector<array<int, 3>> E;
    for (int i = 0; i < M; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        E.push_back({c, --a, --b});
    }
    sort(E.begin(), E.end());
    reverse(E.begin(), E.end());
    for (int i = 0; i < N; i++) pr[i] = -1;
    long sm = 0;
    for (auto [c, a, b] : E) {
        a = find(a), b = find(b);
        if (a != b) {
            sm += c;
            pr[a] = b;
        }
    }
    cout << sm * 2 << "\n";
}