#include <bits/stdc++.h>
using namespace std;
int n;
const double eps = 1e-14;
vector<pair<long long, int> > a(1005);
double ans[1005];
int x[1005], y[1005];
double p[1005];
bool valid(int i, int j) {
  int x1 = x[a[i].second];
  int y1 = y[a[i].second];
  int x2 = x[a[j].second];
  int y2 = y[a[j].second];
  double dis = pow(x2 - x1, 2) + pow(y2 - y1, 2);
  long long td = a[j].first - a[i].first;
  if ((double)(pow(td, 2)) - dis > -1e-9) {
    return true;
  } else
    return false;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n;
  for (int i = 0; i < n; i++) {
    int q, w;
    double u;
    long long t;
    cin >> q >> w >> t >> u;
    x[i] = q;
    y[i] = w;
    p[i] = u;
    a[i] = make_pair(t, i);
  }
  sort(a.begin(), a.begin() + n);
  double fans = 0.000000000;
  for (int i = n - 1; i >= 0; i--) {
    ans[i] = p[a[i].second];
    for (int j = i + 1; j < n; j++) {
      if (valid(i, j)) ans[i] = max(ans[i], ans[j] + p[a[i].second]);
    }
    fans = max(fans, ans[i]);
  }
  cout << fixed << setprecision(10) << fans << "\n";
}
