#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr int kMaxN = 2e5 + 3;
vector<int> one[kMaxN];
vector<int> zero[kMaxN];
int cur_w;
int w_id[kMaxN];
int w_s[kMaxN];
bitset<kMaxN> used;
void find_w(int u, int p, vector<int>& nodes) {
  nodes.emplace_back(u);
  for (int v : one[u]) {
    if (v != p) {
      find_w(v, u, nodes);
    }
  }
}
void find_b(int u, int p, vector<int>& nodes, vector<int>& other) {
  nodes.emplace_back(u);
  for (int v : zero[u]) {
    if (v != p) {
      find_b(v, u, nodes, other);
    }
  }
  for (int v : one[u]) {
    other.emplace_back(w_id[v]);
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i < n; ++i) {
    int u, v, c;
    cin >> u >> v >> c;
    --u, --v;
    if (c == 1) {
      one[u].emplace_back(v);
      one[v].emplace_back(u);
    } else {
      zero[u].emplace_back(v);
      zero[v].emplace_back(u);
    }
  }
  ll total = 0;
  for (int i = 0; i < n; ++i) {
    if (!used[i]) {
      vector<int> nodes;
      find_w(i, -1, nodes);
      for (int v : nodes) {
        used[v] = true;
        w_id[v] = cur_w;
      }
      w_s[cur_w] = nodes.size();
      ++cur_w;
      ll k = nodes.size();
      total += k * (k - 1);
    }
  }
  used.reset();
  for (int i = 0; i < n; ++i) {
    if (!used[i]) {
      vector<int> nodes;
      vector<int> ones;
      find_b(i, -1, nodes, ones);
      for (int v : nodes) {
        used[v] = true;
      }
      sort(ones.begin(), ones.end());
      ones.resize(unique(ones.begin(), ones.end()) - ones.begin());
      ll k = nodes.size();
      total += k * (k - 1);
      for (int w : ones) {
        total += (k - 1) * (w_s[w] - 1);
      }
    }
  }
  cout << total << '\n';
  return 0;
}
