#include<bits/stdc++.h>
using namespace std;
const int N=5001,M=1e6;
int n,m,fa[N],ans,cnt;
bool vis[N];
struct node{
	int x,y,z;
}edge[M];
bool cmp(node a,node b)
{
	return a.z<b.z;
}
int find(int x)
{
	if(x==fa[x]) return x;
	else return fa[x]=find(fa[x]);
}
void merge(int x,int y)
{
	int fx=find(x),fy=find(y);
	fa[fx]=fy;
}
int main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)
		fa[i]=i;
	for(int i=1;i<=m;i++)
	{
		cin>>edge[i].x>>edge[i].y>>edge[i].z;
	}
	sort(edge+1,edge+1+m,cmp);
	for(int i=1;i<=n;i++)
		fa[i]=i;
	for(int i=1;i<=m;i++)
	{
		int x=find(edge[i].x);
		int y=find(edge[i].y);
		if(x==y) continue;
		fa[x]=y;
		ans+=edge[i].z;
	}
	cout<<ans<<endl;
	return 0;
}