#include <fstream>
#include <queue>
#include <algorithm>
#include <vector>
using namespace std;
ifstream fin("apm.in");
ofstream fout("apm.out");
int n,m;

const int nmax = 200000;
const int INF = 1e9;

vector <pair<int,int>> v[nmax + 5];

bool viz[nmax + 5];
int d[nmax + 5];


struct elem{
int nod;
int c;

bool operator<(const elem& b) const
{
    return c>b.c;
}

};



int main()
{
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y,c;
        fin>>x>>y>>c;
        v[x].push_back({c,y});
        v[y].push_back({c,x});
    }
    for(int i=1;i<=n;i++)
        d[i]=INF;
    d[1]=0;
    priority_queue <elem> q;
    q.push({1,0});
    while(!q.empty())
    {
        int fr= q.top().nod;
        q.pop();
        if(viz[fr])
            continue;
        viz[fr]=true;
        for(auto& i : v[fr])
            if(i.first < d[i.second] && !viz[i.second])
                d[i.second]=i.first,q.push({i.second,i.first});
    }
    int s=0;
    for(int i=1;i<=n;i++)
        s+=d[i];
    fout<<s;

}