#include <iostream>
#include <algorithm>
#include <fstream>
using namespace std;
const int maxn = 1e5;
int ranks[maxn];
int parent[maxn];
struct edge {
    int from, to, w;
    edge(int a = 0, int b = 0, int c = 0) {
        from = a;
        to = b;
        w = c;
    }
    bool operator<(edge a) {
        return a.w > w;
    }
};
void make_set(int v) {
    ranks[v] = 0;
    parent[v] = v;
}
int find_set(int v) {
    if(parent[v] == v) return v;
    return parent[v] = find_set(parent[v]);
}
void onion_set(int a, int b) {
    a = find_set(a);
    b = find_set(b);
    if (a != b) {
       if (ranks[a] < ranks[b]) swap(a, b);
        parent[b] = a;
        if (ranks[a] == ranks[b]) ranks[a]++;
    }
}
edge e[maxn];
int main() {
    int n,m, ans = 0;
    ifstream in("spantree2.in");
    ofstream out("spantree2.out");
    in >> m >> n;
    for(int i = 0; i < m; i++) {
        make_set(i + 1);
    }
    for(int i = 0; i < n; i++) {
        int a, b, c;
        in >> a >> b >> c;
        e[i] = edge(a, b, c);
    }
    sort(e, e + n);
    for(int i = 0; i < n; i++) {
        int v = e[i].from;
        int u = e[i].to;
        int w = e[i].w;
        if (find_set(v) != find_set(u)) {
            ans += w;
            onion_set(v, u);
        }
    }
    out << ans;
    return 0;
}