#include <bits/stdc++.h>
using namespace std;
struct _ {
  _() { ios_base::sync_with_stdio(0); }
} _;
template <class A, class B>
ostream &operator<<(ostream &o, pair<A, B> t) {
  o << "(" << t.first << ", " << t.second << ")";
  return o;
}
template <class T>
void PV(T a, T b) {
  while (a != b) cout << *a++, cout << (a != b ? " " : "\n");
}
template <class T>
inline bool chmin(T &a, T b) {
  return a > b ? a = b, 1 : 0;
}
template <class T>
inline bool chmax(T &a, T b) {
  return a < b ? a = b, 1 : 0;
}
template <class T>
string tostring(T first, int len = 0) {
  stringstream ss;
  ss << first;
  string r = ss.str();
  if (r.length() < len) r = string(len - r.length(), '0') + r;
  return r;
}
template <class T>
void convert(string first, T &r) {
  stringstream ss(first);
  ss >> r;
}
const int inf = 0x3f3f3f3f;
const int mod = int(1e9) + 7;
const int N = 1111;
int n;
int first[N], xx[N];
int second[N], yy[N];
int t[N], tt[N];
double p[N], pp[N];
int d[N][N];
int rk[N];
double dp[N];
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) cin >> first[i] >> second[i] >> t[i] >> p[i];
  vector<pair<int, int>> v;
  for (int i = 0; i < n; i++) v.push_back(make_pair(t[i], i));
  sort((v).begin(), (v).end());
  for (int i = 0; i < n; i++) rk[v[i].second] = i;
  for (int i = 0; i < n; i++) {
    xx[rk[i]] = first[i];
    yy[rk[i]] = second[i];
    tt[rk[i]] = t[i];
    pp[rk[i]] = p[i];
  }
  for (int i = 0; i < n; i++) {
    first[i] = xx[i];
    second[i] = yy[i];
    t[i] = tt[i];
    p[i] = pp[i];
  }
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) {
      if (i == j) continue;
      long long dist2 =
          (long long)(first[i] - first[j]) * (first[i] - first[j]) +
          (long long)(second[i] - second[j]) * (second[i] - second[j]);
      if ((long long)(t[j] - t[i]) * (t[j] - t[i]) >= dist2) d[i][j] = 1;
    }
  for (int i = 0; i < n; i++) {
    dp[i] = p[i];
    for (int j = 0; j < n; j++) {
      if (d[j][i]) chmax(dp[i], dp[j] + p[i]);
    }
  }
  double res = 0;
  for (int i = 0; i < n; i++) chmax(res, dp[i]);
  cout << fixed << setprecision(15) << res << endl;
  return 0;
}
