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

using edge = tuple<int, int, int>;
const int N = 2e5 + 10;

int fa[N];

int find(int x) {
    return fa[x] > 0 ? find(fa[x]) : x;
}

int n, m;

vector<edge> e;

int main() {
    memset(fa, -1, sizeof fa);
    cin >> n >> m;
    for(int i = 1, u, v, w; i <= m; i ++) {
        cin >> u >> v >> w;
        e.push_back({w, u, v});
    }
    sort(e.begin(), e.end());
    long long ans = 0;
    for(auto &[w, u, v] : e) {
        int fu = find(u), fv = find(v);
        if(fu == fv) continue;
        ans += (long long)w * fa[fu] * fa[fv];
        if(fa[fu] < fa[fv]) swap(fu, fv);
        fa[fv] += fa[fu];
        fa[fu] = fv;
    }
    cout << ans;
}