#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int MAXS = 1 << 16;
const int MAXN = 1e5 + 5;
int dp[MAXS] , n , S , a[MAXN];
int DP(int now) {
	if(now == 0) return 0;
	if(dp[now] != -1) return dp[now];
	dp[now] = 1e9;
	for (int i = 0; i < 15; ++i) {
		if(!(now & (1 << i))) continue;
		for (int j = i + 1; j < 15; ++j) {
			if(!(now & (1 << j))) continue;
			int nnow = now ^ (1 << i) ^ (1 << j) ^ (1 << (((i+1) ^ (j+1)) - 1));
			int f;
			if(((now ^ (1 << i) ^ (1 << j)) & (1 << (((i+1) ^ (j+1)) - 1)))) f = 1;
			else f = 0;
			dp[now] = min(dp[now] , DP(nnow) + 1 + f);
		}
	}
	return dp[now];	
}
int main() {
	scanf("%d" , &n);
	for (int i = 1; i < n; ++i) {
		int u , v , w;
		scanf("%d %d %d" , &u , &v , &w);
		a[u] ^= w;
		a[v] ^= w;
	}
	int ans = 0;
	for (int i = 0; i < n; ++i) {
		if(!a[i]) continue;
		if(S & (1 << (a[i] - 1))) ans ++;
		S ^= (1 << (a[i] - 1));
	} 
	memset(dp , -1 , sizeof dp);
	dp[0] = 0;
	ans += DP(S);
	printf("%d" , ans);
	return 0;
}