#include <bits/stdc++.h>
using namespace std;
const int INF = 2000000000;
using namespace std;
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string& s) { return '"' + s + '"'; }
string to_string(const char* s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto& x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
long long n;
vector<int> adj[200005];
vector<bool> visited;
vector<int> ans;
void dfs(int v) {
  visited[v] = true;
  for (int u : adj[v]) {
    if (!visited[u]) dfs(u);
  }
  ans.push_back(v);
}
void topological_sort() {
  visited.assign(n, false);
  ans.clear();
  for (int i = 0; i < n; ++i) {
    if (!visited[i]) dfs(i);
  }
  reverse(ans.begin(), ans.end());
}
long long p2(long long x) { return x * x; }
long long dist2(pair<long long, long long> p, pair<long long, long long> q) {
  return p2(p.first - q.first) + p2(p.second - q.second);
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  vector<long long> t(n);
  vector<double> p(n);
  vector<pair<long long, long long> > x(n);
  for (int i = (0); i < (int)(n); i++) {
    long long ti, xi, yi;
    double pi;
    cin >> xi >> yi >> ti >> pi;
    t[i] = ti, p[i] = pi;
    x[i] = {xi, yi};
  }
  for (int i = (0); i < (int)(n); i++) {
    for (int j = (0); j < (int)(n); j++) {
      if (t[i] < t[j] && p2(t[i] - t[j]) >= dist2(x[j], x[i]))
        adj[i].push_back(j);
    }
  }
  vector<double> dp(n, 0);
  for (int i = (0); i < (int)(n); i++) dp[i] = p[i];
  topological_sort();
  for (int iii = (0); iii < (int)(n); iii++) {
    long long i = ans[iii];
    for (auto j : adj[i]) dp[j] = max(dp[j], dp[i] + p[j]);
  }
  for (int i = (0); i < (int)(n); i++) 42;
  42;
  42;
  double out = dp[0];
  for (int i = (0); i < (int)(n); i++) out = max(out, dp[i]);
  cout << fixed << setprecision(10) << out << endl;
  return 0;
}
