#include <bits/stdc++.h>
using namespace std;
#define LOCAL
#pragma region Macros
typedef long long ll;
#define ALL(x) (x).begin(),(x).end()
const long long MOD=1e9+7;
// const long long MOD=998244353;
const int INF=1e9;
const long long IINF=1e18;
const int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
const char dir[4]={'D','R','U','L'};

template<typename T>
istream &operator>>(istream &is,vector<T> &v){
    for (T &x:v) is >> x;
    return is;
}
template<typename T>
ostream &operator<<(ostream &os,const vector<T> &v){
    for (int i=0;i<v.size();++i){
        os << v[i] << (i+1==v.size()?"": " ");
    }
    return os;
}
template<typename T,typename U>
ostream &operator<<(ostream &os,const pair<T,U> &p){
    os << '(' << p.first << ',' << p.second << ')';
    return os;
}
template<typename T,typename U>
ostream &operator<<(ostream &os,const map<T,U> &m){
    os << '{';
    for (auto itr=m.begin();itr!=m.end();++itr){
        os << '(' << itr->first << ',' << itr->second << ')';
        if (++itr!=m.end()) os << ',';
        --itr;
    }
    os << '}';
    return os;
}
template<typename T>
ostream &operator<<(ostream &os,const set<T> &s){
    os << '{';
    for (auto itr=s.begin();itr!=s.end();++itr){
        os << *itr;
        if (++itr!=s.end()) os << ',';
        --itr;
    }
    os << '}';
    return os;
}

void debug_out(){cerr << '\n';}
template<class Head,class... Tail>
void debug_out(Head&& head,Tail&&... tail){
    cerr << head;
    if (sizeof...(Tail)>0) cerr << ", ";
    debug_out(move(tail)...);
}
#ifdef LOCAL
#define debug(...) cerr << " ";\
cerr << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]" << '\n';\
cerr << " ";\
debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

template<typename T> T gcd(T x,T y){return y!=0?gcd(y,x%y):x;}
template<typename T> T lcm(T x,T y){return x/gcd(x,y)*y;}

template<class T1,class T2> inline bool chmin(T1 &a,T2 b){
    if (a>b){a=b; return true;} return false;
}
template<class T1,class T2> inline bool chmax(T1 &a,T2 b){
    if (a<b){a=b; return true;} return false;
}
#pragma endregion

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N; cin >> N;
    vector<vector<pair<int,int>>> G(N);
    for (int i=0;i<N-1;++i){
        int x,y,a; cin >> x >> y >> a;
        G[x].emplace_back(y,a);
        G[y].emplace_back(x,a);
    }
    vector<int> cnt(16,0);
    auto dfs=[&](auto self,int v,int p,int a)->void{
        for (auto e:G[v]){
            int u=e.first;
            if (u==p) continue;
            self(self,u,v,e.second);
            a^=e.second;
        }
        ++cnt[a];
    };
    dfs(dfs,0,-1,0);
    int bit=0,ans=0;
    for (int i=1;i<16;++i){
        ans+=cnt[i]>>1;
        bit|=(cnt[i]&1)<<i;
    }
    vector<int> dp(1<<16,20);
    dp[0]=0;
    for (int mask=1;mask<(1<<16);++mask){
        int XOR=0;
        for (int i=0;i<16;++i){
            if (mask&1<<i) XOR^=i;
        }
        if (XOR) continue;
        for (int i=1;i<16;++i){
            for (int j=i+1;j<16;++j){
                if (!(mask&1<<i)||!(mask&1<<j)) continue;
                for (int k=1;k<16;++k){
                    int nmask=mask,pre=1;
                    nmask^=1<<i; nmask^=1<<j;
                    if (nmask&1<<(i^k)) ++pre;
                    nmask^=1<<(i^k);
                    if (nmask&1<<(j^k)) ++pre;
                    nmask^=1<<(j^k);
                    if (nmask&1) nmask^=1;
                    if (nmask>mask) continue;
                    dp[mask]=min(dp[mask],dp[nmask]+pre);
                }
            }
        }
    }
    cout << ans+dp[bit] << '\n';
}

Measured memory_bytes: 19092