#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
int main(){
	int N, M;
	cin >> N >> M;
	vector<tuple<int, int, int>> E;
	for (int i = 0; i < M; i++){
		int a, b, c;
		cin >> a >> b >> c;
		a--;
		b--;
		E.push_back(make_tuple(c, a, b));
	}
	sort(E.rbegin(), E.rend());
	atcoder::dsu uf(N);
	long long sum = 0;
	for (auto [c, a, b] : E){
		if (!uf.same(a, b)){
			uf.merge(a, b);
			sum += c * 2;
		}
	}
	cout << sum << endl;
}