#include <bits/stdc++.h>

#define int long long
#define pb push_back
#define F first
#define S second

using namespace std;

int32_t main ()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    int n, m;
    cin >> n >> m;
    vector <pair<int, pair<int, int>>> g;
    for (int i=0; i<m; i++)
    {
        int x, y, z;
        cin >> x >> y >> z;
        x--, y--;
        g.pb({z, {x, y}});
    }
    sort (g.begin(), g.end());
    int root[n];
    for (int i=0; i<n; i++)
    {
        root[i] = i;
    }
    int ans = 0;
    int i = 0;
    for (int j=0; j<n-1; j++)
    {
        while (root[g[i].S.F] == root[g[i].S.S]) i++;
        ans += g[i].F;
        int mx = max (root[g[i].S.F], root[g[i].S.S]), mn = min (root[g[i].S.F], root[g[i].S.S]);
        for (int v=0; v<n; v++)
        {
            if (root[v] == mx) root[v] = mn;
        }
    }
    cout << ans;
}