#include <bits/stdc++.h>
#define REP(i, n)     for(int i = 0;i < n;i++)
#define REPR(i, n)    for(int i = n;i >= 0;i--)
#define FOR(i, m, n)  for(int i = m;i < n;i++)
#define FORR(i, m, n) for(int i = m;i >= n;i--)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define VRSORT(v) sort(v.begin(), v.end(),greater<long long>());
#define ALL(X) (X).begin(),(X).end()
#define INF 99999999
#define M_PI 3.14159265358979323846
#define MOD 1000000007

#ifdef __LOCAL
    #define DBG(X) cout << #X << " = " << (X) << endl;
    #define SAY(X) cout << (X) << endl;
#else
    #define DBG(X)
    #define SAY(X)
#endif

#ifdef __LOCAL
    #include <filesystem>
    namespace fs = std::filesystem;
#endif

using namespace std;

using ll = long long int;
using ull = unsigned long long int;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

int dx[]={1, 0, -1, 0, 0};
int dy[]={0, 1, 0, -1, 0};
const int INT_INF = (int)(2e9);
const ll  LL_INF = (ll)(2e18);
const int NIL = -1;
static mt19937 _g(time(nullptr));
 
std::string pad(int num){ char buffer[4]; std::snprintf(buffer, sizeof(buffer), "%03d", num); return buffer;}
inline ll randint(ll a, ll b) { ll w = (_g() << 31LL) ^ _g(); return a + w % (b - a + 1); }
inline void fast_io() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); };
template<typename T> inline T sign(T x) { return T(x > 0) - T(x < 0); }
template<typename T, typename S> inline ostream& operator<<(ostream& os, const pair<T, S> p) { cout << "[" << p.first << ";" << p.second << "]"; return os; }
template<typename T, typename S> inline ostream& operator<<(ostream& os, const map<T, S> p) { for (auto el : p) os << "[" << el.first << " " << el.second << "]"; return os; }
template<typename T> inline ostream& operator<<(ostream& os, const vector<T>& v) { for (auto el : v) os << el << " "; return os; }
template<typename T> inline T fetch() { T ret; cin >> ret; return ret; }
template<typename T> inline vector<T> fetch_vec(int sz) { vector<T> ret(sz); for (auto& elem : ret) cin >> elem; return ret; }

struct point{
    double x,y;
    complex<double> z;
    double theta;
    point(double x=0, double y=0):x(x),y(y){complex<double> w(x,y);z=w; calc_theta();}
    void calc_theta(){theta=arg(z);}
    double dist(){return sqrt(x*x+y*y);}
    double dist2(){return (x*x+y*y);}
    point operator+=(const point& a){x+=a.x;y+=a.y; return *this;}
};

int N;
vector<point> X;

void input(){
    fast_io();
    #ifdef __LOCAL
        fs::path p = __FILE__;
        fs::path input,output;
        input = output = p.parent_path();
        input += string("/input/") + string(p.stem()) + string(".txt");
        output += string("/output/") + string(p.stem()) + string(".txt");
        freopen(input.c_str(), "r", stdin);
        freopen(output.c_str(), "w", stdout);
    #endif
    cin >> N ;
    for(int i=0;i<N;i++){
        int x,y;
        cin >> x >> y;
        X.emplace_back(x,y);
    }
}

double diff_theta(double a,double b){
    if(a*b>=0) return abs(a-b);
    else{
        if(b<0) swap(a,b);
        return min(b-a,2*M_PI-b+a);
    }
}
double eps = 1e-9;
void solve(){
    double ans=0;
    auto cmp = [&](point a, point b){return a.theta < b.theta;};
    sort(X.begin(),X.end(),cmp);
    for (int i = 0; i < N; i++)
    {
        point z;
        for (int j = i; j < 2*N; j++)
        {
            point tmp=z;
            tmp+=X[j%N];
            if(tmp.dist2()>=z.dist2()) z=tmp;
            else break;
            if(j==(N+i-1)) break;
        }
        ans = max(ans,z.dist2());
        
    }
    
    // for (int i = -180000; i <= 180000; i++)
    // {
    //     double arg = (double)i/360000*M_PI;
    //     point po;
    //     for(auto p:X) {
            
    //         if(diff_theta(arg,p.theta)<M_PI_2-eps) {po+=p;}
    //         }
    //     ans = max(ans,po.dist2());
    // }
    cout << setprecision(12) << sqrt(ans) << endl;    

}


int main()
{
    input();
    solve();
    return 0;
}


Measured memory_bytes: 768