#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
using namespace std;
#define MAXM 100000
#define MAXN 10000
#define LL long long int
struct edge
{
     int leftnode;
     int rightnode;
     int data;
     edge();
};
edge::edge()
{
     leftnode=0;
     rightnode=0;
     data=0;
}
int min(int a,int b){return a<b?a:b;}
int max(int a,int b){return a>b?a:b;}
edge a[MAXM+1];
int n,m,father[MAXN+1],times=0;
LL ans=0;
int getfather(int x)
{
     if(father[x]==x)
        return x;
     else
        return father[x]=getfather(father[x]);
}
void hebin(int x,int y)
{
     father[getfather(x)]=father[getfather(y)];
}
int cmp(const void *a,const void *b)
{
     return (*(edge *)a).data-(*(edge *)b).data;
}
int main()
{    
     freopen("kruskal.in","r",stdin);
     freopen("kruskal.out","w",stdout);
     cin>>n>>m;
     for(int i=0;i<m;i++)
     {
         cin>>a[i].leftnode>>a[i].rightnode>>a[i].data;
     }
     qsort(a,m,sizeof(edge),cmp);
     int t=0;
     while(times!=n-1)
     {
         if(getfather(a[t].leftnode)!=getfather(a[t].rightnode))
         {
             ans+=a[t].data;
             hebin(a[t].leftnode,a[t].rightnode);
             times++;
         }
         t++;
     }
     cout<<ans<<endl;
}