#include <bits/stdc++.h>
using namespace std;
#define ll long long
struct node{
	ll from,to,v;
}a[2000010];
bool cmp(node a,node b){
	return a.v<b.v;
}
ll fa[2000010];
ll find(ll x){
	if(fa[x]==x){
		return x;
	}
	else{
		fa[x]=find(fa[x]);
		return fa[x];
	}
}
void un(ll x,ll y){
	fa[find(x)]=find(y);
}
bool b[2000010];
ll n,m,ans,t;
int main( ){
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		fa[i]=i;
	}
	for(int i=1;i<=m;i++){
		cin>>a[i].from>>a[i]. to>>a[i].v;
//		fa[a[i].from]=a[i].to;
	}
	sort(a+1,a+m+1,cmp);
	for(int i=1;i<=m;i++){
		if(find(a[i].from)!=find(a[i].to)){
			ans+=a[i].v;
			un(a[i].from,a[i].to);
			t++;
			if(t==n-1) break;
		}
	}
	cout<<ans;
	
	return 0;
}