#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const deque<T> &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename T> void ndarray(vector<T> &vec, int len) { vec.resize(len); }
template<typename T, typename... Args> void ndarray(vector<T> &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); }
template<typename T> bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template<typename T> bool mmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }
template<typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template<typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
#define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl;
#define FI first
#define SE second
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((lint)(x).size())
#define POW2(n) (1LL << (n))

int N;
map<int, vector<pint>> edges;

vector<int> xors;

int next_combination(int comb)
{
    int x = comb & -comb, y = comb + x;
    return ((comb & ~y) / x >> 1) | y;
}

constexpr int D = 15;

int main()
{
    cin >> N;
    REP(i, N - 1)
    {
        int x, y, a;
        cin >> x >> y >> a;
        edges[x].emplace_back(y, a);
        edges[y].emplace_back(x, a);
    }
    xors.resize(N);
    REP(i, N) for (auto e : edges[i]) xors[i] ^= e.second;

    vector<int> cou(D);
    for (auto v : xors) if (v) cou[v - 1]++;

    vector<int> dp(POW2(D), 100);
    dp[0] = 0;

    FOR(npop, 3, D + 1)
    {
        int S = POW2(npop) - 1;
        while (S < POW2(D))
        {
            REP(d, D) if (S & POW2(d)) FOR(d1, d + 1, D) if (S & POW2(d1))
            {
                int new_a = ((d + 1) xor (d1 + 1)) - 1;
                if (S & POW2(new_a)) mmin(dp[S], dp[S xor POW2(d) xor POW2(d1) xor POW2(new_a)] + 2);
                else mmin(dp[S], dp[S xor POW2(d) xor POW2(d1) xor POW2(new_a)] + 1);
            }
            S = next_combination(S);
        }
    }
    int ans = 0;
    int S = 0;
    REP(i, D)
    {
        ans += cou[i] / 2;
        S += POW2(i) * (cou[i] % 2);
    }
    cout << ans + dp[S] << endl;
}


Measured memory_bytes: 14452