#include<bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1e9 + 7;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    cerr << fixed << setprecision(20);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}

using Point = pair< int64, int64 >;
using Polygon = vector< Point >;

Point operator-(const Point &a, const Point &b) {
  return Point(a.first - b.first, a.second - b.second);
}

Point operator+(const Point &a, const Point &b) {
  return Point(a.first + b.first, a.second + b.second);
}

int64 cross(const Point &a, const Point &b) {
  return a.first * b.second - a.second * b.first;
}

Polygon convex_hull(Polygon &p) {
  int n = (int) p.size(), k = 0;
  if(n <= 2) return p;
  sort(p.begin(), p.end());
  vector< Point > ch(2 * n);
  for(int i = 0; i < n; ch[k++] = p[i++]) {
    while(k >= 2 && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) <= 0) --k;
  }
  for(int i = n - 2, t = k + 1; i >= 0; ch[k++] = p[i--]) {
    while(k >= t && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) <= 0) --k;
  }
  ch.resize(k - 1);
  return ch;
}


int main() {
  int N;
  cin >> N;
  Polygon p(N);
  cin >> p;
  Polygon po{Point(0, 0), p[0]};
  for(int i = 1; i < N; i++) {
    Polygon po2(po);
    for(auto &q : po) po2.emplace_back(q + p[i]);
    po = convex_hull(po2);
  }
  double ret = 0.0;
  for(auto &q : po) chmax(ret, sqrt(q.first * q.first + q.second * q.second));
  cout << ret << endl;
}







Measured memory_bytes: 256