#include <iostream>
#include <fstream>
//#include <cstring>
//#include <cmath>
#include <algorithm>
using namespace std;
ifstream fin("date.in");
//ofstream fout("date.out");
const int mxn=1e3;
const int nax=1e5;
struct muchie{
    int x,y;
    int c;
}v[nax];
int L[nax], n, m;
bool comparare(muchie a, muchie b){
    return a.c < b.c;
}
int main(){
    int i, j;
    int ax,ay;
    fin>>n>>m;
    for(i=1;i<=m;++i){
        fin>>v[i].x>>v[i].y>>v[i].c;
    }
    sort(v, v+m, comparare);
    for(i=1;i<=n;++i)
        L[i]=i;
    int ct=0, k=0;
    for(i=1;i<=n && k<n; ++i){
        if(L[v[i].x] != L[v[i].y]){
            ct+=v[i].c;
            ax=L[v[i].x]; ay=L[v[i].y];
            for(j=1;j<=n;++j)
                if(L[j]==ay)
                    L[j]=ax;
        }
    }
    cout<<ct<<"\n";
    cout<<endl; return 0;
}