#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll n,top1,top2,q1[500005],q2[500005],tb[500005],tot,md;
ll ans;
struct node{
	ll x,y;
	node operator - (const node &b)const{
		return {x-b.x,y-b.y};
	}
	ll operator * (const node &b)const{
		return x*b.y-y*b.x;
	}
}p[500005];
bool cmp(node x,node y){
	return x.x==y.x?x.y<y.y:x.x<y.x;
}
ll dis(node x,node y){
	return (x.x-y.x)*(x.x-y.x)+(x.y-y.y)*(x.y-y.y);
}
int main(){
	scanf("%lld",&n);
	for(ll i=1;i<=n;i++)
		scanf("%lld%lld",&p[i].x,&p[i].y);
	sort(p+1,p+1+n,cmp);
	for(ll i=1;i<=n;i++){
		if(!(i<n&&p[i].x==p[i+1].x)){
			while(top1>1&&(p[q1[top1]]-p[q1[top1-1]])*(p[i]-p[q1[top1]])>=0)top1--;
			q1[++top1]=i;
		}
		if(!(i>1&&p[i].x==p[i-1].x)){
			while(top2>1&&(p[q2[top2]]-p[q2[top2-1]])*(p[i]-p[q2[top2]])<=0)top2--;
			q2[++top2]=i;
		}
	}
	for(ll i=1;i<=top1;i++)tb[++tot]=q1[i];
	md=tot;
	if(q1[top1]!=q2[top2])tb[++tot]=q2[top2];
	for(ll i=top2-1;i>1;i--)tb[++tot]=q2[i];
	if(q1[1]!=q2[1])tb[++tot]=q2[1];
	
	for(ll i=1,j=md;i<=md;i++){
		while(j<tot&&(p[tb[i+1]]-p[tb[i]])*(p[tb[j]]-p[tb[j-1]])>=0)ans=max(ans,dis(p[tb[i]],p[tb[j]])),j++;
		ans=max(ans,dis(p[tb[i]],p[tb[j]]));
	}
	printf("%lf",sqrt(ans));
}