#include<iostream>
#include<vector>
#include<queue>
using namespace std;

struct UF{
    vector<int> p;
    int n;

    UF(int siz){
        n = siz;
        p.resize(n);
        for(int i = 0; i < n; i++)  p[i] = i;
    }

    int findSet(int x){
        if(p[x] != x)   p[x] = findSet(p[x]);
        return p[x];
    }

    bool same(int x, int y){
        return findSet(x) == findSet(y);
    }

    void unite(int x, int y){
        x = findSet(x), y = findSet(y);
        p[x] = y;
    }
};

int main(){
    int v, e;
    cin >> v >> e;
    UF uf(v);
    priority_queue<pair<int,pair<int,int>>> q;
    while(e-- > 0){
        int s, t, w;
        cin >> s >> t >> w;
        q.push({-w, {s, t}});
    }
    int ans = 0;
    while(!q.empty()){
        auto p = q.top();   q.pop();
        int i = p.second.first, j = p.second.second;
        if(uf.same(i,j))    continue;
        uf.unite(i,j);
        ans -= p.first;
    }
    cout << ans << endl;
    return 0;
}
