#pragma GCC target( "sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")

#include <bits/stdc++.h>

using namespace std;

#define speed ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define sz(x) (int)(x.size())
#define all(x) x.begin(), x.end()

typedef long long ll;
typedef unsigned long long ull;


const ll INF = LLONG_MAX;
const int inf = INT_MAX;
const int N = 3e5+5;
const int MOD = 1e9+7;
const double EPS = 1e-9;

vector <vector <pair <ll, ll> > > g(N);
vector <ll> mins(N, INF);
bool used[N];

void solve(){
    ll n, m, u, v, w, st = -1, ans = 0;
    set <ll> se;
    vector <ll> vert;
    cin >> n >> m;
    while(m--){
        cin >> u >> v >> w;
        g[u].pb({v, w});
        g[v].pb({u, w});
        if(st == -1)
            st = u;
        mins[u] = min(mins[u], w);
        mins[v] = min(mins[v], w);
        se.insert(u);
        se.insert(v);
    }

    vert.insert(vert.begin(), all(se));

    mins[st] = 0;

    for(int i = 0; i < n; i++){
        ll v = -1;
        for(int j = 0; j < n; j++)
            if(!used[vert[j]] && (v == -1 || mins[vert[j]] < mins[v]))
                v = vert[j];

        used[v] = 1;

        for(auto x : g[v]){
            ll to = x.F, len = x.S;
            if(len < mins[to])
                mins[to] = len;

        }
    }


    for(int i = 0; i < n; i++)
        ans += mins[vert[i]];

    cout << ans << '\n';
}

int main(){
    speed;

    int T = 1;


    while(T--)
        solve();
    return 0;
}