#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;

class Dis{
  public:
  vector<ll> rank,p,siz;
  
  Dis(int s){
    rank.resize(s,0);
    p.resize(s,0);
    siz.resize(s,1);
    rep(i,s) makeSet(i);
  }
  
  void makeSet(int x){
    p[x]=x;
    rank[x]=0;
  }
  
  bool same(int x,int y){
    return findSet(x)==findSet(y);
  }
  
  void unite(int x,int y){
    if(same(x,y)) return;
    link(findSet(x),findSet(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 findSet(int x){
    if(x != p[x]) p[x]=findSet(p[x]);
    return p[x];
  }
  
  int size(int x){
    return siz[findSet(x)];
  }
};

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

  int n,m;
  cin>>n>>m;
  vector<pair<ll,pair<int,int>>> G(m);
  rep(i,m){
    int a,b;
    ll w;
    cin>>a>>b>>w;
    a--,b--;
    G[i]={w,{a,b}};
  }
  Dis ds=Dis(n);
  
  sort(ALL(G));
  ll ans=0,sum=0;
  rep(i,m){
    auto [a,b]=G[i].second;
    ll w=G[i].first;
    if(ds.findSet(a)==ds.findSet(b)) continue;
    ans+=w*ds.size(a)*ds.size(b);
    ds.unite(a,b);
  }
  cout<<ans<<endl;

  return 0;
}