#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 10, inf = 0x3f3f3f3f, mod = 1000000007;
const long long INF = 0x3f3f3f3f3f3f3f3f;
const double eps = 1e-9;
void read() {}
template <typename T, typename... T2>
inline void read(T &x, T2 &...oth) {
  x = 0;
  int ch = getchar(), f = 0;
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = 1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = (x << 1) + (x << 3) + (ch ^ 48);
    ch = getchar();
  }
  if (f) x = -x;
  read(oth...);
}
struct node {
  int x, y, t;
  double p;
} rec[maxn];
double dp[maxn];
signed main(signed argc, char const *argv[]) {
  std::ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> rec[i].x >> rec[i].y >> rec[i].t >> rec[i].p;
  }
  sort(rec + 1, rec + n + 1,
       [](const node &a, const node &b) { return a.t < b.t; });
  double ans = 0;
  for (int i = 1; i <= n; i++) {
    dp[i] = rec[i].p;
    for (int j = 1; j < i; j++) {
      long long x = (rec[i].x - rec[j].x), y = (rec[i].y - rec[j].y);
      double T = rec[i].t - rec[j].t;
      if (T * T >= x * x + y * y) dp[i] = max(dp[i], dp[j] + rec[i].p);
    }
    ans = max(ans, dp[i]);
  }
  cout << setiosflags(ios::fixed) << setprecision(9) << ans << endl;
  return 0;
}
