#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;
}p[500005];
bool cmp(node x,node y){
	return x.x==y.x?x.y<y.y:x.x<y.x;
}
ll dx(ll x,ll y){
	return p[x].x-p[y].x;
}
ll dy(ll x,ll y){
	return p[x].y-p[y].y;
}
ll get_d(ll x,ll y){
	return dx(x,y)*dx(x,y)+dy(x,y)*dy(x,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&&dy(q1[top1],q1[top1-1])*dx(i,q1[top1])<dy(i,q1[top1])*dx(q1[top1],q1[top1-1]))top1--;
			q1[++top1]=i;
		}
		if(!(i>1&&p[i].x==p[i-1].x)){
			while(top2>1&&dy(q2[top2],q2[top2-1])*dx(i,q2[top2])>dy(i,q2[top2])*dx(q2[top2],q2[top2-1]))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&&dy(tb[i+1],tb[i])*dx(tb[j],tb[j+1])<dy(tb[j],tb[j+1])*dx(tb[i+1],tb[i]))ans=max(ans,get_d(tb[i],tb[j])),j++;
		ans=max(ans,get_d(tb[i],tb[j]));
	}
	printf("%lf",sqrt(ans));
}