KRUSKAL

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

int pr[10000];



struct edge {
    int u, v, w;
    bool operator<(const edge& p) const
    {
        return w < p.w;
    }
};


vector<edge> e;

int find(int r)
{
    return (pr[r] == r) ? r : find(pr[r]);
}

int mst(int n)
{
    sort(e.begin(), e.end());

    for (int i = 1; i <= n; i++)
        pr[i] = i;

    int count = 0, s = 0;

    for (int i = 0; i < (int)e.size(); i++) {

        int u = find(e[i].u);

        int v = find(e[i].v);

        if (u != v) {
            pr[u] = v;

            count++;

            s += e[i].w;

            if (count == n - 1)
                break;
        }
    }
    return s;
}

int main()
{
    // READ("in");
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int n, m;

    cin >> n >> m;

    for (int i = 1; i <= m; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        edge get;
        get.u = u;
        get.v = v;
        get.w = w;
        e.push_back(get);
    }


    cout << mst(n) << endl;
    return 0;
}