#include "testlib.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, a, b) for(ll i = a; i < (b); i++)

struct DSU {
    vector<int> par;
    DSU(int n) : par(n) {
        iota(par.begin(), par.end(), 0);
    }
    int find(int x) {
        if (par[x] == x) return x;
        return par[x] = find(par[x]);
    }
    void unite(int x, int y) {
        par[find(x)] = find(y);
    }
    bool same(int x, int y) {
        return find(x) == find(y);
    }

    int groups() {
        set<int> s;
        for (int i = 0; i < (int)par.size(); i++) {
            s.insert(find(i));
        }
        return s.size();
    }
};

const int min_n = 1;
const int max_n = 500'000;

const int min_w = -1'000'000'000;
const int max_w = 1'000'000'000;

int main(){
    registerValidation();

    int n = inf.readInt(min_n, max_n);
    inf.readEoln();

    DSU uf(n);
    
    rep(i, 0, n-1) {
        cerr << i << endl;
        int u = inf.readInt(1, n);
        inf.readSpace();
        int v = inf.readInt(1, n);
        inf.readSpace();
        inf.readInt(min_w, max_w);
        inf.readEoln();
        
        u--; v--;
        assert(!uf.same(u, v));
        uf.unite(u, v);
    }

    assert(uf.groups() == 1);

    inf.readEof();
}