#include <bits/stdc++.h>
using namespace std;
vector<long long> v[1001];
vector<pair<double, pair<double, double> > > temp;
long long vis[1001] = {0};
double tp[1001][2][2];
double dis(long long i, long long j) {
  return (temp[i].second.first - temp[j].second.first) *
             (temp[i].second.first - temp[j].second.first) +
         (temp[i].second.second - temp[j].second.second) *
             (temp[i].second.second - temp[j].second.second);
}
void dfs(long long cur) {
  long long i, j;
  double g[2][2];
  for (i = 0; i < 2; i++) {
    for (j = 0; j < 2; j++) g[i][j] = 0;
  }
  for (long long x : v[cur]) {
    dfs(x);
    for (i = 0; i <= 1; i++) {
      for (j = 0; j <= 1; j++) g[i][j] += tp[x][i][j];
    }
  }
  double r = temp[cur].first;
  for (i = 0; i <= 1; i++) {
    for (j = 0; j <= 1; j++) {
      tp[cur][i][j] =
          max(g[i ^ 1][j] + r * r * (i == 0 ? double(1) : double(-1)),
              g[i][j ^ 1] + r * r * (j == 0 ? double(1) : double(-1)));
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(NULL);
  long long i, j, n, m;
  cin >> n;
  for (i = 0; i < n; i++) {
    double x, y, z;
    cin >> x >> y >> z;
    temp.push_back(make_pair(z, make_pair(x, y)));
  }
  sort(temp.begin(), temp.end());
  for (i = 0; i < n; i++) {
    for (j = 0; j < i; j++) {
      double r = temp[i].first;
      if (dis(i, j) <= r * r && vis[j] == 0) v[i].push_back(j), vis[j] = 1;
    }
  }
  double ans = 0;
  for (i = 0; i < n; i++) {
    if (vis[i] == 0) {
      dfs(i);
      ans += tp[i][0][0];
    }
  }
  cout << setprecision(10) << ans * double(3.1415926535897);
  return 0;
}
