//kruskal tree
#include <cstdio>
#include <algorithm>
using namespace std;
#define M 100000
int parent[M],a[M],b[M];
pair<int,int>node[M];
int root(int a){return parent[a]==a?a:parent[a]=root(parent[a]);}
int unite(int a,int b){
	int x=root(a),y=root(b);
	if(x==y)return 0;
	parent[x]=y;
	return 1;
}
int main(){
	int i,s,n,m;
	for(;scanf("%d%d",&n,&m)>1;printf("%d\n",s)){
		for(i=0;i<m;i++)scanf("%d%d%d",a+i,b+i,&node[i].first),node[i].second=i;
		sort(node,node+m);
		for(i=0;i<n;i++)parent[i]=i;
		for(s=i=0;i<m;i++)if(unite(a[node[i].second],b[node[i].second]))s+=node[i].first;
	}
}
#include <cstdio>
#include <vector>
#include <algorithm>
#include <queue>
#include <utility>

using namespace std;

template <class T>
using gp_queue=priority_queue<T, deque<T>, less<T>>;

using Weight=long long;
static const Weight INF=1LL<<57;

struct Edge {
    size_t src, dst;
    Weight weight;
    Edge() {}
    Edge(size_t src, size_t dst, Weight weight=1):
        src(src), dst(dst), weight(weight)
    {}
};

bool operator<(const Edge &e, const Edge &f) {
    if (e.weight != f.weight) {
        return e.weight > f.weight;
    } else {
        return e.src!=f.src? e.src<f.src : e.dst<f.dst;
    }
}

using Edges=vector<Edge>;
using Vertex=vector<Edge>;
using Graph=vector<Vertex>;

void join(Graph &g, size_t s, size_t d, Weight w=1) {
    // non-directed
    g[s].push_back(Edge(s, d, w));
    g[d].push_back(Edge(d, s, w));
}

void connect(Graph &g, size_t s, size_t d, Weight w=1) {
    // directed
    g[s].push_back(Edge(s, d, w));
}

pair<Weight, Edges> minimum_spanning_tree(const Graph &g, size_t s=0) {
    /* Prim */
    size_t V=g.size();
    Edges T;
    Weight total=0;

    vector<bool> visited(V);
    gp_queue<Edge> q; q.push(Edge(-1, s, 0));
    while (!q.empty()) {
        Edge e=q.top(); q.pop();
        if (visited[e.dst]) continue;

        T.push_back(e);
        total += e.weight;
        visited[e.dst] = true;
        for (const Edge &f: g[e.dst])
            if (!visited[f.dst])
                q.push(f);
    }

    return make_pair(total, T);
}

int main() {
    size_t V, E;
    scanf("%zu %zu", &V, &E);

    Graph g(V);
    for (size_t i=0; i<E; ++i) {
        size_t s, t;
        Weight w;
        scanf("%zu %zu %lld", &s, &t, &w);

        join(g, s, t, w);
    }

    printf("%lld\n", minimum_spanning_tree(g).first);
    return 0;
}