#include <bits/stdc++.h>
using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
typedef vector<int> vi;

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define rep(i,n) rep2(i,0,n)
#define rep2(i,m,n) for(int i=m;i<(n);i++)
#define ALL(c) (c).begin(),(c).end()

const int MN = 100010;

int N;
int val[MN];
int num[16];
int dp[1 << 15];
int ret;
bool zero[1 << 15];

int main() {
	cin >> N;

	rep(i, N-1) {
		int a, b, e;
		cin >> a >> b >> e;
		val[a] ^= e;
		val[b] ^= e;
	}

	rep(i, N) num[val[i]]++;
	
	int f = 0;

	for (int i = 1; i < 16; ++i) {
		ret += num[i] / 2;
		num[i] %= 2;
		f |= (num[i] << (i-1));
	}

	rep(i, 1 << 15) {
		int xo = 0;
		rep(j, 15) {
			if ((i >> j) & 1) {
				xo ^= (j + 1);
			}
		}
		zero[i] = (xo == 0);
	}

	for (int i = 1; i < (1<<15); ++i) {
		for (int j = i; j >= 0; --j) {
			j &= i;
			if (j == 0) break;
			if (zero[j]) {
				dp[i] = max(dp[i], dp[i^j] + 1);
			}
		}
	}

	cout << ret + __builtin_popcount(f) - dp[f] << endl;

	return 0;

}