#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int N=100005;
int val[N],cnt[N],sxr[1<<17];
int a[17];
int dp[1<<17];
inline int read(){
	int x=0;char e=getchar();
	for (;e<'0'||e>'9';e=getchar());
	for (;e>='0'&&e<='9';e=getchar()) x=(x<<1)+(x<<3)+(e^48);
	return x;
}
inline int Min(int a,int b){
	return a<b?a:b;
}
int main (){
	int n=read();
	for (int i=1;i<n;i++){
		int u=read()+1,v=read()+1,w=read();
		val[u]^=w,val[v]^=w;
	}
	for (int i=1;i<=n;i++) cnt[val[i]]++;
	int ans=0,to=0;
	for (int i=1;i<16;i++){
		ans+=(cnt[i]>>1);
		if (cnt[i]&1) to|=(1<<i);
	}
	for (int i=0;i<(1<<16);i++)
		for (int j=0;j<16;j++)
			if (i&(1<<j)) sxr[i]^=j;
	for(int i=0;i<(1<<16);i++) dp[i]=dp[i>>1]+(i&1);
    for(int i=1;i<(1<<16);i++) dp[i]--;
	for (int i=0;i<(1<<16);i++){
        if (sxr[i]) continue;
        for (int k=(i-1)&i;k;k=(k-1)&i)
            if (!sxr[k]) dp[i]=Min(dp[i],dp[k]+dp[i^k]);
	}
	printf ("%d",dp[to]+ans);
	return 0;
}