#include<bits/stdc++.h>

using namespace std;
const int N = 2e5+100;
const double  eps  = (1e-10);
//点
struct Point{
    double x,y;
    Point(double _x=0,double _y=0):x(_x),y(_y){}
    Point operator + (Point p){return Point(x+p.x,y+p.y);}
    Point operator - (Point p){return Point(x-p.x,y-p.y);}
    Point operator * (double a){return Point(a*x,a*y);}
    Point operator / (double a){return Point(x/a,y/a);}
    double norm(){return x*x+y*y;}//模的平方
    double ABS() {return sqrt(norm());}//模
};
//线段
struct Segment{
    Point p1,p2;
};
double dot(Point a,Point b){
    return a.x*b.x+a.y*b.y;
}
double cross(Point a,Point b){
    return a.x*b.y-a.y*b.x;
}
vector<Point> G;
//旋转卡壳计算凸包直径
double Diameter(vector<Point> G){
    double ans=0;
    int n=G.size();
    for(int i=0,k=0;i<n;i++){
        while((G[i]-G[k]).norm()<(G[i]-G[(k+1)%n]).norm()) k=(k+1)%n;
        ans=max(ans,(G[i]-G[k]).ABS());
    }
    return ans;
}
int main(){
    int n;scanf("%d",&n);
    double x,y;
    for(int i=1;i<=n;i++){
        scanf("%lf %lf",&x,&y);
        G.push_back({x,y});
    }
    double ans=Diameter(G);
    printf("%.10lf\n",ans);
    return 0;
}
