#include <bits/stdc++.h>
using namespace std;
const long long Mod = 7 + 1e9;
const long long INF32 = 5 + 2e9;
const long long INF64 = 1 + 5e3;
const long long MAX = 5 + 3e5;
int N, boss[MAX], sz[MAX];
vector<pair<int, bool> > G[MAX];
int DFS1(int u, int pre, int BOSS) {
  boss[u] = BOSS;
  int sum = 0;
  for (auto v : G[u])
    if (v.first != pre && v.second == 1) sum += DFS1(v.first, u, BOSS) + 1;
  return sum;
}
int cnt;
bool vis[MAX];
int DFS2(int u, int pre) {
  vis[u] = 1;
  cnt += sz[boss[u]];
  int sum = 1;
  for (auto v : G[u])
    if (v.first != pre && v.second == 0) sum += DFS2(v.first, u);
  return sum;
}
int main() {
  cin >> N;
  for (int i = 0; i < N - 1; i++) {
    int u, v, w;
    cin >> u >> v >> w;
    G[u].push_back({v, w});
    G[v].push_back({u, w});
  }
  long long ans = 0;
  for (int i = 1; i <= N; i++)
    if (boss[i] == 0) sz[i] = DFS1(i, i, i);
  for (int i = 1; i <= N; i++)
    if (!vis[i]) {
      cnt = 0;
      long long temp = DFS2(i, i);
      ans += temp * cnt;
      ans += temp * (temp - 1);
    }
  cout << ans << endl;
  return 0;
}
