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

struct edge {
    int a, b, w;
    edge(int a, int b, int w) : a(a), b(b), w(w) {}
    bool operator<(edge y) {
        return w < y.w;
    }
};

vector<int> f;

int findroot(int x) {
    return f[x] == x ? x : f[x] = findroot(f[x]);
}

int main() {
    int n, m;
    while (cin >> n >> m) {
        vector<edge> road;
        f.resize(n + 1);  // 初始化并查集
        for (int i = 1; i <= n; i++) f[i] = i;
        int component_count = n;  // 连通分量计数
        while (m--) {
            int a, b, w;
            cin >> a >> b >> w;
            road.push_back(edge(a, b, w));
        }
        sort(road.begin(), road.end());
        int ans = 0;
        for (auto x : road) {
            int fa = findroot(x.a);
            int fb = findroot(x.b);
            if (fa != fb) {
                component_count--;
                f[fa] = fb;
                ans +=...