#include <bits/stdc++.h>
using namespace std;
int n, u, v, c;
long long int dp[200010][5];
vector<int> edge[200010], col[200010];
long long int ans = 0;
void dfs(int cn, int par = -1) {
  long long tans = ans;
  for (int i = 0; i < edge[cn].size(); i++) {
    int to = edge[cn][i];
    int color = col[cn][i];
    if (to == par) continue;
    dfs(to, cn);
    long long ttans = 0;
    if (color == 0) {
      ttans = 2 * (dp[cn][0] + 1) * (dp[to][0] + 1) +
              (dp[cn][0] + 1) * (dp[to][1] + dp[to][2]) +
              (dp[to][0] + 1) * (dp[cn][1] + dp[cn][2]);
      dp[cn][0] += dp[to][0] + 1;
      dp[cn][2] += dp[to][2] + dp[to][1];
    } else {
      ttans = 2 * (dp[cn][1] + 1) * (dp[to][1] + 1) +
              dp[cn][0] * (dp[to][1] + 1) + (dp[to][0]) * (dp[cn][1] + 1) +
              dp[cn][3] * (dp[to][1] + 1) + (dp[to][3]) * (dp[cn][1] + 1);
      dp[cn][1] += dp[to][1] + 1;
      dp[cn][3] += dp[to][3] + dp[to][0];
    }
    ans += ttans;
  }
}
int main() {
  cin >> n;
  for (int i = 1; i < n; i++) {
    cin >> u >> v >> c;
    edge[u].push_back(v);
    edge[v].push_back(u);
    col[u].push_back(c);
    col[v].push_back(c);
  }
  dfs(1);
  cout << ans << endl;
}
