#include <bits/stdc++.h>
using namespace std;
int n,m;
struct point{
	int u,v,w;
	bool operator<(const point& p)const{
		return w>p.w;
	}
};
int f[1000005];
int find(int x){
	return x==f[x]?x:f[x]=find(f[x]);
}
void join(int x,int y){
	int fx=find(x);
	int fy=find(y);
	if(fx!=fy)f[fx]=fy;
}
int main(){
	cin>>n>>m;
	for(int i=0;i<=n;i++)f[i]=i;
	int u,v,w;
	priority_queue<point>q;
	while(m--){
		cin>>u>>v>>w;
		q.push({u,v,w});
	}
	int k=1;
	int res=0;
	while(k!=n){
		point p=q.top();q.pop();
		if(find(p.u)!=find(p.v)){
			join(p.u,p.v);
			res+=p.w;
			k++;
		}
	}
	cout<<res<<endl;
	return 0;
}
