#include <bits/stdc++.h>

 #define LL long long

 #define INF 0x3f3f3f3f3f3f3f

 #define pii pair<int,int>

 using namespace std;

 const int maxn = ;

 struct arc{

     int to,cost,next;

     arc(int x = ,int y = ,int z = -){

         to = x;

         cost = y;

         next = z;

     }

 }e[];

 int tot,n,m,head[maxn];

 LL d[maxn];

 bool done[maxn];

 void add(int u,int v,int cost){

     e[tot] = arc(v,cost,head[u]);

     head[u] = tot++;

     e[tot] = arc(u,cost,head[v]);

     head[v] = tot++;

 }

 priority_queue< pii,vector< pii >,greater< pii > >q;

 LL prim(){

     while(!q.empty()) q.pop();

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

         done[i] = false;

         d[i] = INF;

     }

     q.push(make_pair(d[] = ,));

     LL ans = ;

     while(!q.empty()){

         int u = q.top().second;

         q.pop();

         if(done[u]) continue;

         done[u] = true;

         ans += d[u];

         for(int i = head[u]; ~i; i = e[i].next){

             if(!done[e[i].to] && e[i].cost < d[e[i].to]){

                 d[e[i].to] = e[i].cost;

                 q.push(make_pair(d[e[i].to],e[i].to));

             }

         }

     }

     return ans;

 }

 int main(){

     int u,v,w;

     while(~scanf("%d %d",&n,&m)){

         memset(head,-,sizeof(head));

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

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

             add(u,v,w);

         }

         printf("%I64d\n",prim());

     }

     return ;

 }