#include <iostream>
#include <queue>
#include <vector>
using namespace std;
const int maxn = 1e5 + 10;
const int INF = 1e9;
int root[maxn];
int sz[maxn];
int find_root(int x) {
    while(root[x] != x) {
        root[x] = root[root[x]];
        x = root[x];
    }
    return x;
}
bool check(int A, int B) {
    int root_A = find_root(A);
    int root_B = find_root(B);
    return root_A == root_B;
}
void unite(int A, int B) {
    int root_A = find_root(A);
    int root_B = find_root(B);
    if(root_A != root_B) {
        if(sz[root_A] > sz[root_B]) {
            root[root_B] = root[root_A];
            sz[root_A] += sz[root_B];
        }
        else {
            root[root_A] = root[root_B];
            sz[root_B] += sz[root_A];
        }
    }


}
int main() {
    for(int i = 0; i < maxn; i++) {
        root[i] = i;
        sz[i] = 1;
    }

    int n, m;
    cin >> n >> m;
    vector<pair<int, pair<int, int> > > v;
    for(int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        v.push_back(make_pair(c, make_pair(a, b)));
    }
    sort(v.begin(), v.end());
    int MST = 0;
    for(int i = 0; i < n; i++) {
        int a = v[i].second.first;
        int b = v[i].second.second;
        int c = v[i].first;

        if(!check(a, b)) {
            unite(a, b);
            MST += c;
        }
    }
    cout << MST << endl;
    return 0;
}