#include <iostream>
#include <fstream>
#include <vector>
#include <random>
#include <algorithm>
#include <queue>
using namespace std;

typedef pair<int,int> PII;
typedef vector<pair<int,int>> VII;

template<typename T>
void print(vector<T> sez) {
    for (T x : sez) cout << x << " ";
    cout << endl;
}

class DisjointSet {  // union-find
public:
    vector<int> parent, size;
    DisjointSet(int n) {
        parent = vector<int>(n);
        size = vector<int>(n);
        for (int i=0;i<n;i++) {
            parent[i] = i;
            size[i] = 1;
        }
    }

    int root(int x) {
        if (parent[x] == x) return x;
        int r = root(parent[x]);
        parent[x] = r;  // path-compression
        return r;
    }

    void join(int x, int y) {
        x=root(x); y=root(y);
        if (x==y) return;
        if (size[x]>size[y]) swap(x,y);  // x smaller
        parent[x]=y;
        size[y]+=size[x];
    }
};

int Prim(vector<vector<PII>> &adj) {
    int n=adj.size();
    vector<int> dist(n,-1);
    vector<int> done(n);
    priority_queue<PII, vector<PII>, greater<PII>> pq;  // min-heap
    int cost=0;
    dist[0]=0; pq.push({0,0});
    while (!pq.empty()) {
        auto [d,x]=pq.top(); pq.pop();
        if (done[x]) continue;  // ignore old values in pq
        cost+=d;
        done[x]=1;
        for (auto [y,w] : adj[x]) if (!done[y]) {
            if (dist[y]==-1 || w < dist[y]) {
                dist[y]=w; pq.push({w,y});
            }
        }
    }
    return cost;
}

int main() {
    /*
    DisjointSet ds(10);
    ds.join(3,4); ds.join(5,6); ds.join(3,6); ds.join(2,7);
    cout << (ds.root(4) == ds.root(7)) << endl;
    cout << (ds.root(3) == ds.root(5)) << endl;
    */
    ifstream fin("mst.txt");
    int n,m;
    fin >> n >> m;
    vector<vector<PII>> adj(n);
    for (int i=0;i<m;i++) {
        int a,b,w;
        fin >> a >> b >> w;
        adj[a].push_back({b,w});
        adj[b].push_back({a,w});
    }
    //for (auto [x,w] : adj[7]) cout << x << " " << w << endl;
    cout << Prim(adj) << endl;
    return 0;
}