#include <cstdio>

 #include <queue>

 #include <cstring>

 #define heap pair<int, int>

 using namespace std;

 int n, m, cnt, ans;

 int head[], to[], next[], val[];

 bool vis[];

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

 inline void add(int x, int y, int z)

 {

     to[cnt] = y;

     val[cnt] = z;

     next[cnt] = head[x];

     head[x] = cnt++;

 }

 inline void queue_prim()

 {

     int i, u, v, tot = n;

     heap x;

     q.push(make_pair(, ));

     while(!q.empty() && tot)

     {

         x = q.top();

         q.pop();

         u = x.second;

         if(vis[u]) continue;

         vis[u] = ;

         ans += x.first;

         tot--;

         for(i = head[u]; i != -; i = next[i])

         {

             v = to[i];

             if(!vis[v]) q.push(make_pair(val[i], v));

         }

     }

 }

 int main()

 {

     int i, x, y, z;

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

     scanf("%d %d", &n, &m);

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

     {

         scanf("%d %d %d", &x, &y, &z);

         add(x, y, z);

         add(y, x, z);

     }

     queue_prim();

     printf("%d", ans);

     return ;

 }