#include <bits/stdc++.h>
#define st first
#define nd second
#define MP make_pair
#define f(i,a,b) for(int i=a;i<=b;i++)
#define allx(a) a.begin(),a.end()
#define ally(a) a.rbegin(),a.rend()
#define allx_arr(a,n) next_permutation(a,a+n)
#define ally_arr(a,n) next_permutation(a.begin(),a.end())
using namespace std;
typedef long long ll;
const int N=1000005,X=105,dx[4]={0,0,-1,1};
const ll INF=1000000000000000000,mod=1000000007;
vector<int> pri(int n){
	vector<int> prime;
	bool is_prime[n+1];
	for(int i=0;i<=n;i++)is_prime[i]=1;
	for(int i=2;i<=n;i++){
		if(is_prime[i])
			prime.push_back(i);
		for(int j=0;j<prime.size();j++){
			if(prime[j]*i>n)break;
			is_prime[prime[j]*i]=0;
			if(i%prime[j]==0)break;
		}
	}
	return prime;
}
int h[100000],fat[100000];
int find(int x){
	if(fat[x]==x)return x;
	else return fat[x]=find(fat[x]);
}
void init(){
	for(int i=0;i<=99999;i++)fat[i]=i;
	fill(h,h+99999,1);
}
inline bool same(int x,int y){return find(x)==find(y);}
inline void unite(int x,int y){
	int lx=find(x),ly=find(y);
	if(h[lx]<h[ly])fat[lx]=ly;
	else {
		fat[ly]=lx;
		if(h[lx]==h[ly])h[lx]++;
	}
}
inline int pow(int x,int y){
	if(y<2)return max((int)(1),x);
	int cnt=pow(x,y/2);
	if(y%2==0)return cnt*cnt;
	else return cnt*cnt*x;
}
inline int log(int x,int a){
	if(a==x)return 1;
	return log(x,a/x)+1;
}
inline void read(int &a){
	char x;
	int cnt=1,ans=0;
	while(1){
		x=getchar();
		if(x==' ' or x=='\n')break;
		if(x=='-')cnt=-1;
		else ans*=10,ans+=x-'0';
	}
	a=cnt*ans;
}
inline void write(int a,char x){
	string s;
	while(a!=0)s+=a%10+'0',a/=10;
	reverse(s.begin(),s.end());
	for(int i=0;i<s.size();i++)
	    putchar(s[i]);
	putchar(x);
}
#define print_(a,n) for(int i=0;i<n;i++)write(a[i],' ');
#define print_v(a) for(int i=0;i<a.size();i++)write(a[i],' ');
inline int gcd(ll x,ll y){
    return (x==0 or y==0)?x+y:gcd(min(x,y),max(x,y)%min(x,y));
}
inline int lcm(ll a,ll b){return a/gcd(a,b)*b;}
//---------------------以上均为模板----------------------//
int v,e,lx,ly,cost,mincost[N];
vector<pair<int,int> > G[N];
vector<pair<int,pair<int,int> > > edge;
bool used[N];
int prim(){
	int res=0;
	priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > > w;
	w.push(MP(0,1));
	memset(mincost,0x3f,sizeof(mincost));
	mincost[1]=0;
	while(w.size()){
		int x=w.top().nd;
		w.pop();
		if(used[x])continue;
		res+=mincost[x];
		used[x]=1;
		for(int i=0;i<G[x].size();i++){
			int lx=G[x][i].st;
			mincost[lx]=min(mincost[lx],mincost[x]+G[x][i].nd);
			w.push(MP(mincost[lx],lx));
		}
	}
	return res;
}
int kruskal(){
	init();
	int res=0;
	sort(edge.begin(),edge.end());
	for(int i=0;i<edge.size();i++){
		if(!same(edge[i].nd.st,edge[i].nd.nd)){
			res+=edge[i].st;
			unite(edge[i].nd.st,edge[i].nd.nd);
		}
	}
	return res;
}
signed main(){
	read(v),read(e);
	for(int i=0;i<e;i++){
		read(lx),read(ly),read(cost);
		G[lx].push_back(MP(ly,cost));
		G[ly].push_back(MP(lx,cost));
		edge.push_back(MP(cost,MP(lx,ly)));
	}
	cout<<kruskal();
	return 0;
}