#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
int head[N], to[2 * N], nxt[2 * N], w[2 * N], tot;
void add(int x, int y, int z) {
  to[tot] = y, w[tot] = z, nxt[tot] = head[x], head[x] = tot++;
}
long long dp[N][2];
long long ans;
void dfs1(int u, int fa) {
  for (int i = head[u]; ~i; i = nxt[i]) {
    if (to[i] == fa) continue;
    int v = to[i];
    dfs1(v, u);
    if (w[i] == 1) {
      dp[u][1] += dp[v][0] + dp[v][1] + 1;
    } else {
      dp[u][0] += dp[v][0] + 1;
    }
  }
}
void dfs2(int u, int fa) {
  for (int i = head[u]; ~i; i = nxt[i]) {
    if (to[i] == fa) continue;
    int v = to[i];
    if (w[i] == 1) {
      dp[v][1] += (dp[u][1] - dp[v][1]) + (dp[u][0] - dp[v][0]);
    } else {
      dp[v][0] += dp[u][0] - dp[v][0];
    }
    dfs2(v, u);
  }
}
int main() {
  int n, x, y, z;
  scanf("%d", &n);
  for (int i = 0; i <= n; i++) head[i] = -1;
  for (int i = 1; i < n; i++) {
    scanf("%d%d%d", &x, &y, &z);
    add(x, y, z);
    add(y, x, z);
  }
  dfs1(1, 0);
  dfs2(1, 0);
  long long ans = 0;
  for (int i = 1; i <= n; i++) ans += (dp[i][0] + dp[i][1]);
  printf("%lld\n", ans);
  return 0;
}
