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 {{{
#include <iostream>
#include <cassert>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cctype>
#include <cmath>
#include <ctime>
#include <queue>
#include <set>
#include <map>
#include <stack>
#include <string>
#include <bitset>
#include <vector>
#include <complex>
#include <algorithm>
using namespace std;
// }}}
// #define {{{
typedef long long ll;
typedef double db;
typedef pair<int,int> pii;
typedef vector<int> vi;
#define de(x) cout << #x << "=" << x << endl
#define rep(i,a,b) for(int i=a;i<(b);++i)
#define per(i,a,b) for(int i=(b)-1;i>=(a);--i)
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define fi first
#define se second
// }}}

typedef db T;
const db eps = 1e-8;
int sgn(T x){return (x>eps)-(x<-eps);}
struct P{
    T x,y;
    P(){} P(T x,T y):x(x),y(y){}
    void read(){scanf("%lf%lf",&x,&y);}
    P operator - (const P&b) const {return P(x-b.x,y-b.y);}
    P operator + (const P&b) const {return P(x+b.x,y+b.y);}
    T operator * (const P&b) const {return x*b.x+y*b.y;}
    P operator * (const T&k) const {return P(x*k,y*k);}
    T operator ^ (const P&b) const {return x*b.y-y*b.x;}
    bool operator < (const P&b) const {return sgn(y-b.y)?y<b.y:x<b.x;}
};
db abs(P a){return sqrt(a*a);}
typedef vector<P> polygon;
T diameter(polygon A) {
    int n=sz(A);if(n <= 1) return 0;
    int l=0,r=0;rep(i,1,n) (A[i]<A[l])&&(l=i),(A[r]<A[i])&&(r=i);
    db res=abs(A[l]-A[r]);int i=l,j=r;
    do (++(((A[(i+1)%n]-A[i])^(A[(j+1)%n]-A[j]))>=0?j:i))%=n,
        res=max(res,abs(A[i]-A[j]));
    while(i!=l||j!=r);
    return res;
}

int main(){
    int n;scanf("%d",&n);
    polygon A;
    rep(i,0,n){
        P p;p.read();
        A.pb(p);
    }
    printf("%.10f\n",diameter(A));
    return 0;
}