/*

@theme: kruskal

@writer:pprp

@date:2017/8/19

@begin:21:19

@end:21:50

@declare:

*/

#include <bits/stdc++.h>

using namespace std;

const int maxn = ;

const int INF = ;

int n , e;

struct node

{

    int x, y, w;

};

vector<node> vt;

int dad[maxn];//每个结点的父亲集合

bool cmp(const node& n1, const node& n2)

{

    return n1.w < n2.w;

}

int getfather(int x)

{

    if(x == dad[x])

        return x;

    dad[x] = getfather(dad[x]);

    return dad[x];

}

void kruskal()

{

    for(int i = ; i <= n ;i++)

        dad[i] = i;

    int cnt = , ans = ;

    for(int i = ; i <= e ;i++)

    {

        if(getfather(vt[i-].x)!=getfather(vt[i-].y))

        {

            ans += vt[i-].w;

            dad[getfather(vt[i-].x)] = vt[i-].y;

            cnt++;

            if(cnt == n)

            {

                cout << ans << endl;

                return ;

            }

        }

    }

    return ;

}

int main()

{

    freopen("in.txt","r",stdin);

    cin >> n >> e;

    for(int i =  ; i < e; i++)

    {

        node newnode;

        cin >>newnode.x >> newnode.y >> newnode.w;

        vt.push_back(newnode);

    }

    sort(vt.begin(),vt.end(),cmp);

    kruskal();

    return ;

}