#include<iostream.h>
#include<queue>
#include<vector>
#define INF 100000

using namespace std;

struct edge {
	vector<int>Adj;
	vector<int>Cost;
};

struct node{
 int x, y;
};

edge Ed[100];
int N, E;
int key[100];
char F[100];
int P[100], Cost;
int SS[100][100];

class comp{
   public:
   bool operator() ( const node &a, const node &b) 
   {
       return a.y > b.y;
   }
};

void CT(int u) {
	if(F[u] == 1 || u == 1) return;
	F[u] = 1;
	if(P[u] == -1) return;
	Cost += SS[u][P[u]];
	CT(P[u]);
}



int Prim() {
	int i, j, u, v, c,cost;
	Cost =  0;
	priority_queue<node, vector<node>, comp> Q;
	node temp, dum;
	for(i = 1; i<= N; i++)
		key[i] = INF;
	key[1] = 0;
	temp.x = 1;
	temp.y = 0;
	Q.push(temp);
	P[1] = -1;
	while(!Q.empty()) {
		temp = Q.top();
		Q.pop();
		u = temp.x;
		F[u] = 1;
		for(i = 0; i<Ed[u].Adj.size(); i++) {
			v = Ed[u].Adj[i];
			c = Ed[u].Cost[i] + temp.y;
			if(F[v] == 0) {
				if(key[v] > c) {
					dum.x = v;
					dum.y = c;
					key[v] = c;
					P[v] = u;
					Q.push(dum);
				}
			}
		}
	}
	for(i = 1; i<= N; i++) F[i] = 0;
	for(i = 1; i<= N; i++) {
		if(F[i] == 0)
			CT(i);
	}
	return Cost;
}

void main() {
	int c, u, v, n;
	cin>>N>>E;
	n = E;
	while(n--) {
		cin>>u>>v>>c;
		Ed[u].Adj.push_back(v);
		Ed[u].Cost.push_back(c);
		Ed[v].Adj.push_back(u);
		Ed[v].Cost.push_back(c);
		SS[u][v] = SS[v][u] = c;
	}
	cout<<Prim()<<endl;
}