#include<bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;

#define all(v) v.begin(),v.end()
using ll = long long;
using ull = unsigned long long;
using lll = __int128;
using vll=vector<ll>;
using vvll = vector<vector<ll>>;
using P = pair<ll,ll>;
using vp=vector<pair<ll, ll>>;
//using mint=modint1000000007;
//using mint=modint998244353;

const ll INF=1ll<<60;
ll mod10=1e9+7;
ll mod99=998244353;
const double PI = acos(-1);

#define rep(i,n) for (ll i=0;i<n;++i)
#define per(i,n) for(ll i=n-1;i>=0;--i)
#define rep2(i,a,n) for (ll i=a;i<n;++i)
#define per2(i,a,n) for (ll i=a;i>=n;--i)

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }

struct unionfind{
    ll N;
    vector<ll> par,Rank,Size;
    unionfind(ll n):N(n){
        par=vector<ll>(N),Rank=vector<ll>(N,1),Size=vector<ll>(N,1);
        for(int i=0;i<N;i++) par[i]=i;
    };
    ll find(ll x){
        if(par[x]==x) return x;
        else return par[x]=find(par[x]);
    }

    bool same(ll a,ll b){
        return find(a)==find(b);
    }

    void unite(ll a,ll b){
        if(same(a,b))return;
        a=find(a);
        b=find(b);
        ll s=Size[a]+Size[b];
        if(Rank[b]>Rank[a]) par[a]=b;
        else par[b]=a;
        if(Rank[a]==Rank[b]) Rank[a]++;
        Size[find(a)]=s;
    }

    ll size(ll a){
       return Size[find(a)];
    }
};

bool solve(){

   ll N,M;cin>>N>>M;
   vector<ll> A(M),B(M),C(M);rep(i,M) cin>>A[i]>>B[i]>>C[i],A[i]--,B[i]--;
   vll ind(M);rep(i,M) ind[i]=i;
   auto comp = [&](ll i,ll j){
      return C[i]>C[j];
   };
   sort(all(ind),comp);

   unionfind uf(N);
   ll ans=0;
   rep(i,M){
      ll j=ind[i];
     
      if(!uf.same(A[j],B[j])){
         ans+=C[j];
         uf.unite(A[j],B[j]);
      }
   }
   cout << ans*2 << endl;
   return 0;
}



int main(){
   cin.tie(0);
   ios::sync_with_stdio(false);
   ll T=1;//cin>>T;
   rep(i,T) solve();
}