// Prim MST : Priority_queue

#include <iostream>

#include <vector>

#include <queue>

using namespace std;

int ch[30];

struct edge{

int e;

int val;

edge(int a, int b){

e = a;

val = b;

}

bool operator<(const edge &b)const{

return val > b.val;

}

};

int main(){

freopen("input.txt", "rt", stdin);

ios_base::sync_with_stdio(false);

cin.tie(NULL);

int v, ed, a, b, c, ans = 0;

priority_queue<edge> q;

vector<pair<int, int> > map[30];

cin>>v>>ed;

for(int i = 0 ; i < ed; i++){

cin>>a>>b>>c;

map[a].push_back(make_pair(b, c));

map[b].push_back(make_pair(a, c));

}

q.push(edge(1, 0));

while(!q.empty()){

edge tmp = q.top();

q.pop();

int v = tmp.e;

int cost = tmp.val;

if(ch[v] == 0){

ans += cost;

ch[v] = 1;

for(int i = 0; i < map[v].size(); i++){

q.push(edge(map[v][i].first, map[v][i].second));

}

}

}

cout<<ans<<"\n";

return 0;

}