#include <algorithm>

#include <iostream>

#include <cstdio>

using namespace std;

struct node

{

    int x,y,z;

}edge[];

int tot,fa[],i,j,n,m;

int find_fa(int x)

{

    if(fa[x]==x)

    return x;

    else return find_fa(fa[x]);

}

bool cmp(node a,node b)

{

    return a.z<b.z;

}

int main()

{

    ios::sync_with_stdio(false);

    cin>>n>>m;

    int s,e,w;

    for(i=;i<m;++i)

    {

        cin>>s>>e>>w;

        tot++;

        edge[tot].x=s;

        edge[tot].y=e;

        edge[tot].z=w;

    }

    for(i=;i<=n;++i) fa[i]=i;

    sort(edge+,edge++tot,cmp);

    int ans=,h=;

    for(i=;i<=tot;++i)

    {

        int x=find_fa(edge[i].x),y=find_fa(edge[i].y);

        if(x!=y)

        {

            h++;

            fa[y]=x;

            ans+=edge[i].z;

            if(h==n-)

            break;

        }

    }

    cout<<ans;

}