rt

#include<bits/stdc++.h>
#define int long long
#define MAXN 1e9
using namespace std;

struct A{
    int v,len;
    friend bool operator < (const A &x,const A &y){
        return x.len>y.len;
    }
};

vector<A> a[10005];
int n,m;
int f[10005];
int ans;
priority_queue<A> q;

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> m;
    for(int i=1;i<=n;i++){
        int u,v,len;
        cin >> u >> v >> len;
        a[u].push_back({v,len});
        a[v].push_back({u,len});
    }
    q.push({1,0});
    for(int i=1;i<=n;i++){
        A t;
        while(!q.empty()){
            t=q.top();
            q.pop();
            if(f[t.v]==0) break;
        }
        f[t.v]++;
        ans+=t.len;
        for(int j=0;j<a[t.v].size();j++){
            if(f[a[t.v][i].v]==0){
                q.push(a[t.v][i]);
            }
        }
    }
    cout << ans;
    return 0;
}