#include<bits/stdc++.h>
#include<atcoder/dsu>
using namespace std;
using ll=long long;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int N,M;
	cin>>N>>M;
	vector<tuple<ll,int,int>>vt;
	for(int i=0;i<M;i++){
		int a,b;
		ll w;
		cin>>a>>b>>w;
		a--;
		b--;
		vt.push_back(make_tuple(w,a,b));
	}
	sort(vt.begin(),vt.end());
	atcoder::dsu uf(N);
	ll ans=0;
	for(auto[w,a,b]:vt){
		if(uf.same(a,b))continue;
		ans+=w*uf.size(a)*uf.size(b);
		uf.merge(a,b);
	}
	cout<<ans<<"\n";
}