#include <bits/stdc++.h>
using namespace std;
#define N 200010
#define ll long long
int n, num, h[N];
ll ans, f[N][2], g[N][2];
struct Edge {
  int to, nxt, z;
} e[N << 1];
void ins(int x, int y, int z) {
  e[++num].to = y;
  e[num].nxt = h[x];
  e[num].z = z;
  h[x] = num;
  e[++num].to = x;
  e[num].nxt = h[y];
  e[num].z = z;
  h[y] = num;
}
struct node {
  int x;
  ll f1, f2;
} a[N];
bool operator<(node x, node y) { return x.x < y.x; }
void dfs(int x, int fa, int c) {
  f[x][0] = 1ll;
  f[x][1] = 1ll;
  int now = 0;
  for (int i = h[x]; i; i = e[i].nxt) {
    int y = e[i].to;
    if (y == fa) continue;
    dfs(y, x, e[i].z);
    ++now;
    if (e[i].z > c) f[x][0] += f[y][0];
    if (e[i].z < c) f[x][1] += f[y][1];
  }
  if (now) {
    now = 0;
    for (int i = h[x]; i; i = e[i].nxt) {
      int y = e[i].to;
      if (y == fa) continue;
      a[++now] = (node){e[i].z, f[y][0], f[y][1]};
    }
    sort(a + 1, a + now + 1);
    int m = 0;
    for (int i = 1; i <= now; ++i) {
      if (i != 1 && a[i].x == a[i - 1].x) {
        g[m][0] += a[i].f1;
        g[m][1] += a[i].f2;
      } else {
        g[++m][0] = a[i].f1;
        g[m][1] = a[i].f2;
      }
    }
    ll res = 0;
    for (int i = 1; i <= m; ++i) { res += g[i][0] + g[i][1]; }
    for (int i = 2; i <= m; ++i) { g[i][1] += g[i - 1][1]; }
    for (int i = 2; i <= m; ++i) { res += g[i - 1][1] * g[i][0]; }
    ans += res;
  }
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i < n; ++i) {
    int x, y, z;
    scanf("%d%d%d", &x, &y, &z);
    ins(x, y, z);
  }
  dfs(1, 0, 0);
  printf("%lld\n", ans);
  return 0;
}