#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 10;
const int base = 31337;
const int mod = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const int logo = 20;
const int off = 1 << logo;
const int treesiz = off << 1;
int n;
vector<int> graph[maxn][2];
bool bio[maxn];
int col[maxn][2];
int siz[maxn][2];
int dfs(int x, int cl, int b) {
  bio[x] = true;
  col[x][b] = cl;
  int out = 1;
  for (int i = 0; i < graph[x][b].size(); i++) {
    int tren = graph[x][b][i];
    if (!bio[tren]) out += dfs(tren, cl, b);
  }
  return out;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i < n; i++) {
    int a, b, c;
    scanf("%d%d%d", &a, &b, &c);
    graph[a][c].push_back(b);
    graph[b][c].push_back(a);
  }
  for (int a = 0; a < 2; a++) {
    memset(bio, false, sizeof bio);
    for (int i = 1; i <= n; i++) {
      if (!bio[i]) {
        siz[i][a] = dfs(i, i, a);
      }
    }
  }
  long long sol = 0;
  for (int i = 1; i <= n; i++) {
    int px = col[i][0];
    int py = col[i][1];
    sol += (long long)siz[px][0] * siz[py][1];
  }
  printf("%lld\n", sol - n);
  return 0;
}
