Problem: Find the diameter of a convex polygon g. In other words, find a pair of points that have maximum distance between them.

Constraints

* 3 ≤ n ≤ 80000
* -100 ≤ xi, yi ≤ 100
* No point in the g will occur more than once.

Input


n
x1 y1
x2 y2
:
xn yn


The first integer n is the number of points in g.

In the following lines, the coordinate of the i-th point pi is given by two real numbers xi and yi. The coordinates of points are given in the order of counter-clockwise visit of them. Each value is a real number with at most 6 digits after the decimal point.

Output

Print the diameter of g in a line. The output values should be in a decimal fraction with an error less than 0.000001.

Examples

Input

3
0.0 0.0
4.0 0.0
2.0 2.0


Output

4.00


Input

4
0.0 0.0
1.0 0.0
1.0 1.0
0.0 1.0


Output

1.414213562373

Solution (in CPP):

Solution:
#include <cassert>// c
#include <iostream>// io
#include <iomanip>
#include <fstream>
#include <sstream>
#include <vector>// container
#include <map>
#include <set>
#include <queue>
#include <bitset>
#include <stack>
#include <algorithm>// other
#include <complex>
#include <numeric>
#include <functional>
using namespace std;

typedef int32_t i32;typedef int64_t i64;typedef i64 ll;typedef uint32_t uint;typedef uint64_t ull;

#define ALL(c) (begin(c)),(end(c))
#define REP(i,n) FOR(i,0,n)
#define REPr(i,n) FORr(i,0,n)
#define FOR(i,l,r) for(int i=(int)(l);i<(int)(r);++i)
#define FORr(i,l,r) for(int i=(int)(r)-1;i>=(int)(l);--i)
#define EACH(it,o) for(__typeof((o).begin()) it = (o).begin(); it != (o).end(); ++it)
#define IN(l,v,r) ((l)<=(v) && (v)<(r))

//debug
#define DUMP(x)  cerr << #x << " = " << (x)
#define DUMPLN(x)  DUMP(x) <<endl
#define DEBUG(x) DUMP(x) << LINE() << " " << __FILE__
#define DEBUGLN(x) DEBUG(x)<<endl
#define LINE()    cerr<< " (L" << __LINE__ << ")"
#define LINELN()    LINE()<<endl
#define CHECK(exp,act)  if(exp!=act){DUMPLN(exp);DEBUGLN(act);}
#define STOP(e)  CHECK(e,true);if(!(e)) exit(1);

class range {
private:
    struct Iter{
        int v;
        int operator*(){return v;}
        bool operator!=(Iter& itr) {return v < itr.v;}
        void operator++() {++v;}
    };
    Iter i, n;
public:
    range(int n) : i({0}), n({n}) {}
    range(int i, int n) : i({i}), n({n}) {}
    Iter& begin() {return i;}
    Iter& end() {return n;}
};

//output
template<typename T> ostream& operator << (ostream& os, const vector<T>& as){REP(i,as.size()){if(i!=0)os<<" "; os<<as[i];}return os;}
template<typename T> ostream& operator << (ostream& os, const vector<vector<T> >& as){REP(i,as.size()){if(i!=0)os<<endl; os<<as[i];}return os;}
template<typename T> ostream& operator << (ostream& os, const set<T>& ss){EACH(a,ss){if(a!=ss.begin())os<<" "; os<<a;}return os;}
template<typename T1,typename T2> ostream& operator << (ostream& os, const pair<T1,T2>& p){os<<p.first<<" "<<p.second;return os;}
template<typename K,typename V> ostream& operator << (ostream& os, const map<K,V>& m){bool isF=true;EACH(p,m){if(!isF)os<<endl;os<<p;isF=false;}return os;}

//input
char tmp[1000];
#define nextInt(n) scanf("%d",&n)
#define nextLong(n) scanf("%lld",&n) //I64d
#define nextDouble(n) scanf("%lf",&n) 
#define nextChar(n) scanf("%c",&n)
#define nextString(n) scanf("%s",tmp);n=tmp

// values
template<class T> T INF(){assert(false);};
template<> int INF<int>(){return 1<<28;};
template<> ll INF<ll>(){return 1LL<<58;};
template<> double INF<double>(){return 1e16;};

template<class T> T EPS(){assert(false);};
template<> int EPS<int>(){return 1;};
template<> ll EPS<ll>(){return 1LL;};
template<> double EPS<double>(){return 1e-8;};
template<> long double EPS<long double>(){return 1e-8;};


template<typename T> T pmod(T v,T M){return (v%M+M)%M;}

namespace _double_tmpl{
    typedef long double D;
    
    static constexpr D Ae=0;
    D A(D a,D b){return a+b;}D Ainv(D a){return -a;}
    D S(D a,D b){return A(a,Ainv(b));}
    
    static constexpr D Me=1;
    D M(D a,D b){return a*b;}D Minv(D a){return 1.0/a;};

    int sig(D a,D b=0){return a<b-EPS<D>()?-1:a>b+EPS<D>()?1:0;}
    bool eq(D a,D b){return sig(abs(a-b))==0;}

}
using namespace _double_tmpl;
namespace Ps{
    // using namespace _double_tmpl;
    typedef complex<D> P,Vec;

#define X real()
#define Y imag()
    istream& operator >> (istream& is,complex<D>& p){
        D x,y;is >> x >> y;p=P(x,y);return is;
    }
    bool eq(const P& a,const P& b){return sig(a.real(),b.real())==0 && sig(a.imag(),b.imag())==0;}
    // a×b
    D cross(const Vec& a,const Vec& b){return imag(conj(a)*b);}
    // a・b
    D dot(const Vec&a,const Vec& b) {return real(conj(a)*b);}

    int ccw(const P& a,P b,P c){
        b -= a; c -= a;
        if (cross(b,c) > EPS<D>())   return +1;       // counter clockwise
        if (cross(b,c) < -EPS<D>())   return -1;       // clockwise
        if (dot(b,c) < 0)     return +2;       // c--a--b on line
        if (norm(b) < norm(c)) return -2;       // a--b--c on line
        return 0;
    }
}
using namespace Ps;
namespace std{
    bool operator < (const P& a,const P& b){
        return make_pair(a.Y,a.X) < make_pair(b.Y,b.X);
        //return a.X != b.X ? a.X < b.X : a.Y < b.Y;
    }
    bool operator > (const P& a,const P& b){return b<a;}
    bool operator == (const P& a,const P& b){
            return eq(a,b);
    }
};

namespace Polys{
    typedef vector<P> Poly,ConvexPoly;
    
        // O(n)
    // verified by ACAC002 C
    // http://judge.u-aizu.ac.jp/onlinejudge/creview.jsp?rid=899143&cid=ACAC002
    D convex_diameter(const ConvexPoly &pt) {
        const int n = pt.size();
        int is = 0, js = 0;
        FOR(i,1,n){
            if (pt[i].Y > pt[is].Y) is = i;
            if (pt[i].Y < pt[js].Y) js = i;
        }
        D maxd = abs(pt[is]-pt[js]);

        int i, maxi, j, maxj;
        i = maxi = is;j = maxj = js;
        do {
            if (cross(pt[pmod(i+1,n)]-pt[i],pt[pmod(j+1,n)]-pt[j]) >= 0) j = (j+1) % n;
            else i = (i+1) % n;
            if (abs(pt[i]-pt[j]) > maxd) {
                maxd = abs(pt[i]-pt[j]);
                maxi = i; maxj = j;
            }
        } while (i != is || j != js);
        return maxd; /* farthest pair is (maxi, maxj). */
    }

}
using namespace Polys;
stringstream ss;
class Main{
    public:
    void run(){
        int n;cin >> n;
        ConvexPoly ps;
        REP(i,n) {
            P p;cin >> p;
            ps.push_back(p);
        }
        cout << convex_diameter(ps) <<endl;
    }
};

int main(){
 cout <<fixed<<setprecision(20);
 cin.tie(0);
 ios::sync_with_stdio(false);
 Main().run();
 return 0;
}