#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5 + 7;
long long cnt0[MAXN], cnt1[MAXN];
int n, cnt;
bool mrk[MAXN][2];
vector<pair<int, int> > G[MAXN];
vector<int> nodes;
void dfs(int x, int peso) {
  mrk[x][peso] = true;
  cnt++;
  nodes.push_back(x);
  for (pair<int, int> edg : G[x]) {
    int viz = edg.first;
    int pi = edg.second;
    if (pi != peso || mrk[viz][peso]) continue;
    dfs(viz, peso);
  }
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i < n; i++) {
    int xi, yi, zi;
    scanf("%d %d %d", &xi, &yi, &zi);
    G[xi].push_back({yi, zi});
    G[yi].push_back({xi, zi});
  }
  for (int i = 1; i <= n; i++) {
    if (mrk[i][0]) continue;
    cnt = 0;
    dfs(i, 0);
    for (int node : nodes) {
      cnt0[node] = cnt;
    }
    nodes.clear();
  }
  for (int i = 1; i <= n; i++) {
    if (mrk[i][1]) continue;
    cnt = 0;
    dfs(i, 1);
    for (int node : nodes) {
      cnt1[node] = cnt;
    }
    nodes.clear();
  }
  long long ans = -n;
  for (int i = 1; i <= n; i++) {
    ans += cnt0[i] * cnt1[i];
  }
  cout << ans << endl;
}
