// Code by H~$~C
#include <bits/stdc++.h>
using namespace std;

static const int Maxn = 100005;

int n;
int a[Maxn];
int dp[Maxn];

int main() {
  scanf("%d", &n);
  for (int i = 1; i < n; ++i) {
    int u, v, w;
    scanf("%d%d%d", &u, &v, &w);
    ++u, ++v;
    a[u] ^= w, a[v] ^= w;
  }
  
  int ans = 0;
  int allmask = 0;
  for (int i = 1; i <= n; ++i) {
    if (a[i] == 0) {
      ++ans;
    }
    else if (allmask & (1 << a[i] - 1)) {
      allmask ^= (1 << a[i] - 1);
      ++ans;
    }
    else {
      allmask ^= (1 << a[i] - 1);
    }
  }
  
  dp[0] = 0;
  for (int mask = 1; mask < (1 << 15); ++mask) {
    dp[mask] = -1;
    int xorsum = 0;
    for (int i = 0; i < 15; ++i) {
      if (mask >> i & 1) {
        xorsum ^= (i + 1);
      }
    }
    if (xorsum != 0) {
      continue;
    }
    
    for (int smask = mask; smask; smask = (smask - 1) & mask) {
      if (dp[smask] == -1) continue;
      dp[mask] = max(dp[mask], dp[smask] + dp[mask ^ smask]);
    }
    dp[mask] = max(dp[mask], 1);
  }
  
  printf("%d\n", n - (ans + dp[allmask]));
  return 0;
}
