#include <bits/stdc++.h>
const int N = 2e5;
int n, f[N + 5][2];
std::vector<std::pair<int, int>> E[N + 5];
inline void addEdge(int u, int v, int w) {
  E[u].push_back(std::make_pair(v, w));
}
void dfs1(int u, int p) {
  for (const auto &t : E[u]) {
    int v = t.first, w = t.second;
    if (v != p) {
      dfs1(v, u);
      f[u][w]++;
      f[u][w] += (w == 1 ? f[v][1] + f[v][0] : f[v][0]);
    }
  }
}
void dfs2(int u, int p) {
  for (const auto &t : E[u]) {
    int v = t.first, w = t.second;
    if (v != p) {
      f[v][w] +=
          (w == 1 ? f[u][1] - f[v][0] - f[v][1] + f[u][0] : f[u][0] - f[v][0]);
      dfs2(v, u);
    }
  }
}
int main() {
  scanf("%d", &n);
  for (int u, v, w, i = 1; i < n; i++) {
    scanf("%d%d%d", &u, &v, &w);
    addEdge(u, v, w);
    addEdge(v, u, w);
  }
  dfs1(1, 0);
  dfs2(1, 0);
  long long ans = 0;
  for (int i = 1; i <= n; i++) {
    ans += f[i][0] + f[i][1];
  }
  printf("%lld\n", ans);
  return 0;
}
