#include <bits/stdc++.h>
using namespace std;
const int N = 200010;
vector<pair<int, int> > G[N];
long long res = 0LL, dp[N][4];
void dfs(int u, int parent) {
  for (int i = 0; i < G[u].size(); ++i) {
    int v = G[u][i].first;
    int w = G[u][i].second;
    if (v == parent) continue;
    dfs(v, u);
    long long cnt[4] = {0};
    if (w == 0) {
      cnt[0] += dp[v][0] + 1;
      cnt[2] += dp[v][2] + dp[v][3];
    } else {
      cnt[1] += dp[v][0] + dp[v][1];
      cnt[3] += dp[v][3] + 1;
    }
    res += (cnt[0] + cnt[3]) * 2 + cnt[1] + cnt[2];
    res += dp[u][0] * cnt[0] + dp[u][0] * cnt[2] + dp[u][0] * cnt[3];
    res += dp[u][1] * cnt[3];
    res += dp[u][3] * cnt[3];
    res += cnt[0] * dp[u][0] + cnt[0] * dp[u][2] + cnt[0] * dp[u][3];
    res += cnt[1] * dp[u][3];
    res += cnt[3] * dp[u][3];
    for (int j = 0; j < 4; ++j) {
      dp[u][j] += cnt[j];
    }
  }
}
int main() {
  int n;
  cin >> n;
  int a, b, w;
  for (int i = 0; i < n - 1; ++i) {
    cin >> a >> b >> w;
    --a;
    --b;
    G[a].push_back(make_pair(b, w));
    G[b].push_back(make_pair(a, w));
  }
  memset(dp, 0, sizeof(dp));
  dfs(0, -1);
  cout << res << endl;
  return 0;
}
