#include<iostream>
#include<cmath>
#include<algorithm>
using namespace std;
const int N=5e5+5;
int n,m,top,xx,yy;
struct sb{
	double x,y,k;
}e[N],st[N];
inline bool cmp(sb a,sb b){return (a.y==b.y)?(a.x<b.x):(a.y<b.y);}
inline double cross(sb a,sb b,sb c){return (b.x-a.x)*(c.y-a.y)-(c.x-a.x)*(b.y-a.y);}
inline double ddd(sb a,sb b){return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));}
inline double dis(sb a,sb b,sb c){
	double k=(b.y-c.y)/(b.x-c.x);
	double bb=b.y-k*b.x;
	return fabs(k*a.x-a.y+bb)/sqrt(k*k+1);
}
inline bool cmpp(sb a,sb b){
	if(a.k!=b.k)return a.k<b.k;
	if(a.x==b.x)return a.y<b.y;
	return a.x<b.x;
}
signed main(){
	// freopen("in.in","r",stdin);
	// freopen("out.out","w",stdout);
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++)cin>>e[i].x>>e[i].y;
	sort(e+1,e+1+n,cmp);
	st[++top]=e[1];
	xx=st[top].x,yy=st[top].y;
	for(int i=2;i<=n;i++)e[i].k=atan2(e[i].y-yy,e[i].x-xx);
	sort(e+2,e+1+n,cmpp);
	st[++top]=e[2];
	for(int i=3;i<=n;i++){
		while(top>1&&cross(st[top-1],st[top],e[i])<=0)top--;
		st[++top]=e[i];
	}st[++top]=st[1];
	int l=1,r=1;
	double ans=0;
	for(l=1;l<top;l++){
		while(dis(st[r+1],st[l+1],st[l])>=dis(st[r],st[l+1],st[l]))r=r%top+1;
		ans=max({ans,ddd(st[r],st[l]),ddd(st[r],st[l+1])});
	}
	printf("%.7lf",ans);
	return 0;
}/*10
0 0
100 -900
200 -1799
9800 -1799
9900 -900
10000 0
9999 100
9998 199
2 199
1 100
*/