#include<bits/stdc++.h>
#define int long long
#define double long double
#define ffor(i,a,b) for(int i=(a);i<=(b);i++)
#define roff(i,a,b) for(int i=(a);i>=(b);i--)
using namespace std;
const int MAXN=5e5+10;
namespace CALCULATING_GEOMETRY {
	struct Point {int x,y;};
	Point operator +(Point A,Point B) {return {A.x+B.x,A.y+B.y};}
	Point operator -(Point A,Point B) {return {A.x-B.x,A.y-B.y};}
	int operator *(Point A,Point B) {return A.x*B.y-A.y*B.x;}
	bool operator <(Point A,Point B) {if(A.x!=B.x) return A.x<B.x;return A.y<B.y;}
	int tot;Point t[MAXN];
	vector<Point> convex_hull(vector<Point> vc) {
		int n=vc.size();
		sort(vc.begin(),vc.end());
		tot=0; int lst=1;
		ffor(i,0,n-1) {
			if(tot<=lst) t[++tot]=vc[i];
			else {
				while(tot>lst&&(t[tot]-t[tot-1])*(vc[i]-t[tot])<=0) tot--;
				t[++tot]=vc[i];	
			}
		}
		lst=tot;
		roff(i,n-2,0) {
			if(tot<=lst) t[++tot]=vc[i];
			else {
				while(tot>lst&&(t[tot]-t[tot-1])*(vc[i]-t[tot])<=0) tot--;
				t[++tot]=vc[i];	
			}	
		}
		vector<Point> res;
		ffor(i,1,tot-1) res.push_back(t[i]);
		return res;
	}
	struct Line {Point p,d;};
}using namespace CALCULATING_GEOMETRY;
int n; vector<Point> vc;
int p_p_dis(Point A,Point B) {auto calc=A-B;return calc.x*calc.x+calc.y*calc.y;}
int p_l_dis(Point o,Point p1,Point p2) {return abs((o-p1)*(p2-p1));}
#define nxt ((p+1)%vc.size())
signed main() {
	ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
	cin>>n;
	ffor(i,1,n) {
		int x,y;
		cin>>x>>y,vc.push_back({x,y});	
	}
//	vc=convex_hull(vc);
	if(vc.size()==2) return cout<<p_p_dis(vc[0],vc[1]),0;
	int p=0;
	while(p_l_dis(vc[nxt],vc[0],vc[vc.size()-1])>=p_l_dis(vc[p],vc[0],vc[vc.size()-1])) p=nxt;
	int ans=max(p_p_dis(vc[0],vc[p]),p_p_dis(vc[vc.size()-1],vc[p]));
	ffor(i,0,vc.size()-2) {
		if(p_l_dis(vc[nxt],vc[i],vc[i+1])>=p_l_dis(vc[p],vc[i],vc[i+1])) p=nxt;
		ans=max(ans,max(p_p_dis(vc[i],vc[p]),p_p_dis(vc[i+1],vc[p])));
	}
	cout<<fixed<<setprecision(10)<<sqrt(1.0*ans);
	return 0;
}