#include <bits/stdc++.h>
#define il inline
using namespace std;
il void cmax(double &x,double y){x=x>y?x:y;}
const double eps=1e-8;
const int N=5e5+5;
int n,m;double ans;

struct node{
    double x,y;
    il node(){x=y=0;}
    il node(double x,double y) : x(x),y(y) {}
    friend node operator-(const node &a,const node &b){return node(a.x-b.x,a.y-b.y);}
    friend double operator*(const node &a,const node &b){return a.x*b.y-b.x*a.y;}
}a[N];
il bool cmp(node a,node b){return a.x==b.x?a.y<b.y:a.x<b.x;}
il double dis(node a,node b){return sqrtl((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));}
il double get(node a,node b,node c){return (b-a)*(c-a);}
int st[N],top;
il void andrew(){
    sort(a+1,a+1+n,cmp);st[++top]=1;
    for(int i=2;i<=n;++i){
        while(top && get(a[st[top-1]],a[st[top]],a[i])<-eps) --top;
        st[++top]=i;
    }m=top;
    for(int i=n-1;i;--i){
        while(top>m && get(a[st[top-1]],a[st[top]],a[i])<-eps) --top;
        st[++top]=i;
    }--top;
}
il int to(int x){
    while(x<=0) x+=top;
    while(x>top) x-=top;
    return x;
}
il void rot(){
    for(int i=1,j=2;i<=top;++i){
        while(get(a[st[i]],a[st[i+1]],a[st[j]])<get(a[st[i]],a[st[i+1]],a[st[j+1]])) j=(j==top?1:j+1);
        for(int u=-2;u<=2;++u)
            for(int v=-2;v<=2;++v)
                cmax(ans,dis(a[st[to(i+u)]],a[st[to(j+v)]]));
    }
}
int main(){
    //freopen("rot.in","r",stdin);
    scanf("%d",&n);
    for(int i=1;i<=n;++i) scanf("%lf%lf",&a[i].x,&a[i].y);
    andrew();
    rot();
    printf("%.15lf",ans);
    return 0;
}