#include <iostream>
#include <vector>
#include <queue>
using namespace std;
const int maxn = 1e5 + 10;
const int INF = 2e9;
vector<pair<int, int>> graph[maxn];
int n, m;
struct node {
    int idx, cost;
    node () {}
    node(int _idx, int _cost) {
        idx = _idx;
        cost = _cost;
    }
    bool operator < (const node &tmp) const {
        return cost > tmp.cost;
    }
};

void prim() {
    vector<int> distance(n, INF);
    vector<bool> visited(n, false);
    distance[0] = 0;
    priority_queue<node> pq;
    pq.push(node(0, 0));
    
    int mst = 0;
    while(!pq.empty()) {
        node c = pq.top();
        pq.pop();
        
        if(visited[c.idx]) {
            continue;
        }
        visited[c.idx] = true;
        mst += c.cost;
        for(int i = 0; i < (int) graph[c.idx].size(); i++) {
            int neighbour = graph[c.idx][i].first;
            int weight = graph[c.idx][i].second;
            
            if(!visited[neighbour] and weight < distance[neighbour]) {
                pq.push(node(neighbour, weight));
                distance[neighbour] = weight;
            }
        }
    }
    cout << mst << endl;
}
int main() {
    cin >> n >> m;
    for(int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        a--; b--;
        graph[a].push_back(make_pair(b, c));
        graph[b].push_back(make_pair(a, c));
    }
    prim();
    
    return 0;
}
/*
 6 9
 5 4 9
 5 1 4
 1 4 1
 1 2 2
 2 4 3
 2 3 3
 2 6 7
 3 6 8
 4 3 5
 
 **/