#include <bits/stdc++.h>
using namespace std;
const long long NR = 2e5 + 100, oo = 1e9 + 10, MOD = 1e9 + 7;
const long double pi = 2 * acos(0.0);
vector<pair<int, int> > v[NR];
long long n, dp0[NR], dp1[NR];
long long sol;
void dfs1(int nod, int fat) {
  int vecin, cost;
  vector<pair<int, int> >::iterator it;
  dp0[nod] = 1;
  dp1[nod] = 1;
  for (it = v[nod].begin(); it != v[nod].end(); ++it) {
    vecin = (*it).first;
    cost = (*it).second;
    if (vecin == fat) continue;
    dfs1(vecin, nod);
    if (cost == 1) {
      dp1[nod] += dp1[vecin];
      dp0[nod] += dp1[vecin];
    } else {
      dp0[nod] += dp0[vecin];
    }
  }
}
void dfs2(int nod, int fat, int tip, long long sum) {
  int vecin, cost;
  vector<pair<int, int> >::iterator it;
  if (tip == 1) {
    dp0[nod] += sum;
    dp1[nod] += sum;
  }
  if (tip == 0) {
    dp0[nod] += sum;
  }
  for (it = v[nod].begin(); it != v[nod].end(); ++it) {
    vecin = (*it).first;
    cost = (*it).second;
    if (vecin == fat) continue;
    if (cost == 1) {
      dfs2(vecin, nod, 1, dp1[nod] - dp1[vecin]);
    }
    if (cost == 0) {
      dfs2(vecin, nod, 0, dp0[nod] - dp0[vecin]);
    }
  }
  sol += dp0[nod] - 1;
}
int main() {
  int x, y, z, i;
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (i = 1; i < n; ++i) {
    cin >> x >> y >> z;
    v[x].push_back(make_pair(y, z));
    v[y].push_back(make_pair(x, z));
  }
  dfs1(1, 0);
  dfs2(1, 0, -1, 0);
  cout << sol << '\n';
  return 0;
}
