#include<bits/stdc++.h>
#define int long long
#define endl '\n'
#define pr(x) pair<x,x>
#define up(i,j,k,l) for(int i=j;i<=k;i+=l)
#define down(i,j,k,l) for(int i=j;i>=k;i-=l)
using namespace std;
const int N=2e5+10;
int n,m;
struct node{
	int u,v,w;
};
node a[N];
int f[N],t1,t2,ans;
int fd(int x)
{
	if(x==f[x]){
		return x;
	}
	else{
		return f[x]=fd(f[x]);
	}
}
bool cmp(node x1,node x2)
{
	return x1.w<x2.w;
}
void solve()
{
	cin>>n>>m;
	up(i,1,n,1){
		f[i]=i;
	}
	up(i,1,m,1){
		cin>>a[i].u>>a[i].v>>a[i].w;
	}
	sort(a+1,a+m+1,cmp);
	up(i,1,m,1){
		t1=fd(a[i].u);
		t2=fd(a[i].v);
		if(t1!=t2){
			f[t1]=t2;
			ans+=a[i].w;
		}
	}
	cout<<ans<<endl;
	return;
}
signed main()
{
    ios::sync_with_stdio(false);
	cin.tie(0);
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	int _=1;
	//cin>>_;
	up(i,1,_,1){
		solve();
	}
	return 0;
}