#include<cstdio>
#include<algorithm> 

using namespace std;

#define int long long 

int n,m,fa[300005],ans;
struct node{
	int x,y,z;
}h[300005];

bool operator < (node x,node y){
	return x.z<y.z;
}

int get(int x){
	if(x==fa[x])return x;
	return fa[x]=get(fa[x]);
}

void Kruskal(){
	sort(h+1,h+m+1);
	for(int i=1;i<=n;i++)fa[i]=i;
	for(int i=1;i<=m;i++){
		int x=get(h[i].x),y=get(h[i].y);
		if(x==y)continue;
		fa[x]=y;
		ans+=h[i].z;
	}
} 

signed main(){
	scanf("%lld %lld",&n,&m);
	for(int i=1;i<=m;i++)
		scanf("%lld %lld %lld",&h[i].x,&h[i].y,&h[i].z);
	Kruskal();
	printf("%lld",ans);
	return 0;
}