#include <bits/stdc++.h>
const int N = 200200;
const long long mod = 1e9 + 7;
using namespace std;
int n;
int d[N][2];
long long res;
vector<pair<int, int> > v[N];
void dfs(int x, int p) {
  for (auto y : v[x]) {
    if (y.first == p) {
      continue;
    }
    dfs(y.first, x);
    if (y.second == 1) {
      d[x][1] += d[y.first][1] + 1;
    } else {
      d[x][0] += d[y.first][0] + d[y.first][1] + 1;
    }
  }
  res += d[x][0] + d[x][1];
}
void trace(int x, int p, int a, int b) {
  res += a + b;
  for (auto y : v[x]) {
    if (y.first == p) {
      continue;
    }
    if (y.second == 1) {
      b += d[y.first][1] + 1;
    } else {
      a += d[y.first][0] + d[y.first][1] + 1;
    }
  }
  for (auto y : v[x]) {
    if (y.first == p) {
      continue;
    }
    if (y.second == 1) {
      b -= d[y.first][1] + 1;
    } else {
      a -= d[y.first][0] + d[y.first][1] + 1;
    }
    int na = a, nb = b;
    if (y.second == 1) {
      nb += 1;
      na = 0;
    } else {
      na += 1 + nb;
      nb = 0;
    }
    trace(y.first, x, na, nb);
    if (y.second == 1) {
      b += d[y.first][1] + 1;
    } else {
      a += d[y.first][0] + d[y.first][1] + 1;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n;
  for (int i = 1; i < n; i++) {
    int x, y, w;
    cin >> x >> y >> w;
    v[x].push_back({y, w});
    v[y].push_back({x, w});
  }
  dfs(1, 1);
  trace(1, 1, 0, 0);
  cout << res << "\n";
}
