#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<cstring>
#include<algorithm>
#include<queue>
#include<stack>
#include<vector>
#include<map>
#include<set>
#include<ctime>
using namespace std;
inline int read(){
	int x=0,f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=x*10+(ch&15);ch=getchar();}
	return x*f;
}
const int N=5e5+10;
int n,w,x[N],y[N];
long long ans;
inline long long dis(int a,int b){
	return 1ll*(x[a]-x[b])*(x[a]-x[b])+1ll*(y[a]-y[b])*(y[a]-y[b]);
}
signed main()
{
    //srand(time(0)+114514);
    n=read();
    for(register int i=1;i<=n;i++)
		x[i]=read(),y[i]=read();
    int i=3;
    for(register int t=1;t<=3;t++){
        long long maxn=0;
		int p=0;
        for(register int j=1;j<=n;j++){
            w=dis(i,j);
			if(w>maxn){
				maxn=w;
				p=j;
			}
        }
        ans=max(ans,maxn);
		i=p;
    }
    printf("%.15Lf",sqrt(ans));
    return 0;
}