#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const int maxn = 2e5 + 5;
vector<pair<int, int> > v[maxn];
long long ans = 0;
long long endp[2][maxn], startdp[2][maxn];
void dfs(int id, int par) {
  for (auto i : v[id]) {
    if (i.first == par) continue;
    dfs(i.first, id);
  }
  for (auto i : v[id]) {
    if (i.first == par) continue;
    if (i.second) {
      endp[1][id] += 1 + endp[1][i.first] + endp[0][i.first];
      startdp[1][id] += 1 + startdp[1][i.first];
    } else {
      endp[0][id] += 1 + endp[0][i.first];
      startdp[0][id] += 1 + startdp[0][i.first] + startdp[1][i.first];
    }
  }
  for (int i = 0; i < 2; ++i) {
    ans += startdp[i][id];
    ans += endp[i][id];
  }
  for (auto i : v[id]) {
    if (i.first == par) continue;
    if (i.second) {
      long long x = 1 + startdp[1][i.first];
      long long y = 1 + endp[1][i.first] + endp[0][i.first];
      ans += y * (startdp[1][id] - x);
    } else {
      long long x = 1 + startdp[0][i.first] + startdp[1][i.first];
      long long y = 1 + endp[0][i.first];
      ans += y * (startdp[0][id] + startdp[1][id] - x);
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int n;
  cin >> n;
  for (int i = 0; i < n - 1; ++i) {
    int x, y, c;
    cin >> x >> y >> c;
    v[x].emplace_back(y, c);
    v[y].emplace_back(x, c);
  }
  dfs(1, -1);
  cout << ans << '\n';
  ;
  return 0;
}
