#include<cstdio>
#define INF 10000002
#define Nmx 200001

using namespace std;
int n,m,H[Nmx*4],viz[Nmx],nr,dist[Nmx];
struct nod
{
    int inf,cost;
    nod *urm;
};
nod *G[Nmx];
struct ssol
{
    int x,y;
}sol[Nmx];

void add(int x,int y,int c)
{
    nod *aux=new nod;
    aux->inf = y;
    aux->cost = c;
    aux->urm = G[x];
    G[x] = aux;
}

void citire()
{
    int x,y,c;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;++i)
    {
        scanf("%d%d%d",&x,&y,&c);
        add(x,y,c);
        add(y,x,c);
    }
}

void down(int k)
{
    while(k*2<=nr)
    {
        int p=k*2;
        if(p+1<=nr)
            if(dist[H[p+1]]<dist[H[p]])
                p=p+1;
        int aux = viz[H[k]];
        viz[H[k]] = viz[H[p]];
        viz[H[p]] = aux;
        aux = H[k];
        H[k]=H[p];
        H[p]=aux;
        k=p;
    }
}

void up(int k)
{
    while(k>1)
    {
        if(dist[H[k/2]]<=dist[H[k]])
            return;
        int aux = viz[H[k]];
        viz[H[k]] = viz[H[k/2]];
        viz[H[k/2]] = aux;
        aux = H[k];
        H[k]=H[k/2];
        H[k/2]=aux;
        k=k/2;
    }
}

void solve()
{
    int sol=0;
    for(int i=1;i<=n;++i)
        dist[i]=viz[i]=INF;
    dist[1]=0;
    viz[1] = 1;
    H[1]=1;
    nr = 1;
    for(int i=1;i<=n;++i)
    {
        int pzz=0,mn=INF+1;
        pzz = H[1];
        viz[H[nr]] = 1;
        viz[H[1]] = -1;
        H[1] = H[nr];
        nr--;
        sol+=dist[pzz];
        viz[pzz]=1;
        for(nod *p=G[pzz];p;p=p->urm)
        {
            if(dist[p->inf]>p->cost)
            {
                dist[p->inf]=p->cost;
                if(viz[p->inf]==INF)
                {
                    H[++nr]=p->inf;
                    viz[p->inf]=nr;
                }
                up(viz[p->inf]);
            }
        }
    }
    printf("%d\n",sol);
}

int main()
{
    freopen("apm.in","r",stdin);
    freopen("apm.out","w",stdout);
    citire();
    solve();
    return 0;
}