#include <bits/stdc++.h>
using namespace std;
const int N = 3e5;
int n, u, v, tp;
int par[2][N], sz[2][N];
long long ans;
int find_set(int v) {
  if (par[tp][v] == v) return v;
  return par[tp][v] = find_set(par[tp][v]);
}
void union_sets(int a, int b) {
  a = find_set(a);
  b = find_set(b);
  if (sz[tp][a] < sz[tp][b]) swap(a, b);
  par[tp][b] = a;
  sz[tp][a] += sz[tp][b];
}
int main() {
  cin >> n;
  for (int i = 0; i < n; ++i) {
    par[0][i] = par[1][i] = i;
    sz[0][i] = sz[1][i] = 1;
  }
  for (int i = 1; i < n; ++i) {
    cin >> u >> v >> tp;
    --u;
    --v;
    union_sets(u, v);
  }
  for (int i = 0; i < n; ++i) {
    if (par[0][i] == i) ans += (long long)sz[0][i] * (sz[0][i] - 1);
    if (par[1][i] == i) ans += (long long)sz[1][i] * (sz[1][i] - 1);
    tp = 0;
    int v = find_set(i);
    tp = 1;
    int u = find_set(i);
    ans += (long long)(sz[0][v] - 1) * (sz[1][u] - 1);
  }
  cout << ans;
}
