///prime队列优化

#include "iostream"

#include "string.h"

#include "stack"

#include "queue"

#include "string"

#include "vector"

#include "set"

#include "map"

#include "algorithm"

#include "stdio.h"

#include "math.h"

#define ll long long

#define lson l,mid,rt<<1

#define rson mid+1,r,rt<<1|1

#define mem(a) memset(a,0,sizeof(a))

using namespace std;

const int N=;

struct Edge{

    int to;

    int w;

    friend bool operator< (Edge a,Edge b){

        return a.w>b.w;

    }

};

vector<Edge>Map[N];  ///vector[i][j]存图表示从第i个节点出发的第j条边的情况

void Add_Edge(int u,int v,int w){

    Edge e;

    e.to=v,e.w=w;

    Map[u].push_back(e);

}

void prime(int n){

    int ans=;

    Edge now;

    int vis[N];

    mem(vis);

    priority_queue<Edge>Q;

    while(!Q.empty())

        Q.pop();

    for(int i=; i<Map[].size(); i++)

        Q.push(Map[][i]);

    vis[]=;

    n--;

    while(n--){

        now=Q.top();

        Q.pop();

        if(vis[now.to]) while(vis[now.to]){

            now=Q.top();

            Q.pop();

        }

        ans+=now.w;

        vis[now.to]=;

        for(int i=; i<Map[now.to].size(); i++)

            if(!vis[Map[now.to][i].to]) Q.push(Map[now.to][i]);

    }

    printf("%d\n",ans);

}

int main(){

    int n,m,u,v,w;

    while(scanf("%d%d",&n,&m)!=EOF){

        for(int i=; i<m; i++){

            scanf("%d%d%d",&u,&v,&w);

            Add_Edge(u,v,w);

            Add_Edge(v,u,w);

        }

        prime(n);

    }

    return ;

}