#include <bits/stdc++.h>
template <typename Tp>
inline void read(Tp &x) {
  x = 0;
  bool f = true;
  char ch = getchar();
  for (; ch < '0' || ch > '9'; ch = getchar()) f ^= ch == '-';
  for (; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + (ch ^ 48);
  x = f ? x : -x;
}
const int N = 2e5 + 7;
int Head[N], Cnt;
struct Edge {
  int to, nxt, w;
};
Edge e[N << 1];
inline void Add_edge(int x, int y, int w) {
  e[++Cnt] = (Edge){y, Head[x], w}, Head[x] = Cnt;
}
int F0[N], F1[N];
inline void Dfs1(int x, int last) {
  F1[x] = 1;
  for (int i = Head[x]; i; i = e[i].nxt) {
    int v = e[i].to;
    if (v == last) continue;
    Dfs1(v, x);
    if (e[i].w)
      F1[x] += F1[v];
    else
      F0[x] += F1[v] + F0[v];
  }
}
inline void Dfs2(int x, int last) {
  for (int i = Head[x]; i; i = e[i].nxt) {
    int v = e[i].to;
    if (v == last) continue;
    int a, b;
    if (e[i].w)
      a = F0[x], b = F1[x] - F1[v];
    else
      a = F0[x] - F1[v] - F0[v], b = F1[x];
    F0[v] += e[i].w ? 0 : a + b;
    F1[v] += e[i].w ? b : 0;
    Dfs2(v, x);
  }
}
int main() {
  int n;
  read(n);
  for (int i = 1; i < n; ++i) {
    int x, y, w;
    read(x), read(y), read(w);
    Add_edge(x, y, w), Add_edge(y, x, w);
  }
  Dfs1(1, 0);
  Dfs2(1, 0);
  long long Ans = 0;
  for (int i = 1; i <= n; ++i) Ans += F0[i] + F1[i] - 1;
  printf("%lld\n", Ans);
  return 0;
}
