#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ALL(v) v.begin(), v.end()
typedef long long ll;

#include <bits/stdc++.h>
using namespace std;
template <class T> using V=vector<T>;
template <class T> using VV=V<V<T>>;

class Dis{
  public:
  V<ll> rank,p,siz;
  int N;
  
  Dis(int s){
    rank.resize(s,0);
    p.resize(s,0);
    siz.resize(s,1);
    rep(i,s) makeSet(i);
    N=s;
  }
  
  void makeSet(int x){
    p[x]=x;
    rank[x]=0;
  }
  
  bool same(int x,int y){
    return root(x)==root(y);
  }
  
  void unite(int x,int y){
    if(same(x,y)) return;
    link(root(x),root(y));
  }
  
  void link(int x,int y){
    if(rank[x]>rank[y]){
      p[y]=x;
      siz[x]+=siz[y];
    }
    else{
      p[x]=y;
      siz[y]+=siz[x];
      if(rank[x]==rank[y]) rank[y]++;
    }
  }
  
  int root(int x){
    if(x != p[x]) p[x]=root(p[x]);
    return p[x];
  }
  
  int size(int x){
    return siz[root(x)];
  }
  
  VV<int> groups(){
    V<int> root_buf(N),group_size(N);
    rep(i,N){
      root_buf[i]=root(i);
      group_size[root_buf[i]]++;
    }
    VV<int> result(N);
    rep(i,N) result[i].reserve(group_size[i]);
    rep(i,N) result[root_buf[i]].push_back(i);
    result.erase(remove_if(ALL(result),[&](const V<int>& v){return v.empty();}),result.end());
    return result;
  }
};

using Edge=pair<ll,pair<int,int>>;

ll kruskal(int n,vector<Edge> edges){
  sort(ALL(edges));
  reverse(ALL(edges));
  ll res=0;
  int m=edges.size();
  Dis dset=Dis(n);
  
  rep(i,m){
    ll w=edges[i].first;
    int u=edges[i].second.first;
    int v=edges[i].second.second;
    
    if(dset.same(u,v)) continue;
    
    res+=w;
    dset.unite(u,v);
  }
  
  return res;
} 

int main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);

  int n,m;
  cin>>n>>m;
  vector<Edge> edges(m);
  rep(i,m){
    int u,v;
    ll w;
    cin>>u>>v>>w;
    u--,v--;
    edges[i]=Edge(w,{u,v});
  }
  cout<<2*kruskal(n,edges)<<endl;
  
  return 0;
}