#include<bits/stdc++.h>

using namespace std;
int n;
struct node{
    int x,y;
}a[500005];
int N;
inline int read(){
    int x = 0, t = 1;
    char ch=getchar(); 
    while(ch<'0'||ch>'9'){
        if(ch=='-')
            t=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9'){
        x=(x<<1)+(x<<3)+(ch^48);  
        ch=getchar();
    }
    return x*t;
}
double dist(node x,node y){
    return sqrt(1ll*(x.x-y.x)*(x.x-y.x)+1ll*(x.y-y.y)*(x.y-y.y));
}
int main(){
    n=read();
    for(int i=1;i<=n;i++)a[i].x=read(),a[i].y=read();
    N=0;
    for(int i=1;i<=n;i++){
        while(N>=2&&1ll*(a[i].x-a[N].x)*(a[N].y-a[N-1].y)==1ll*(a[N].x-a[N-1].x)*(a[i].y-a[N].y))N--;
        a[++N]=a[i];
    }
    a[N+1]=a[1];
    int now=1,nxet=2;
    double ans=0;
    for(int i=1;i<=N;i++){
        while(nxet!=i&&1ll*(a[i+1].x-a[i].x)*(a[now].y-a[i].y)-1ll*(a[i+1].y-a[i].y)*(a[now].x-a[i].x)<=1ll*(a[i+1].x-a[i].x)*(a[nxet].y-a[i].y)-1ll*(a[i+1].y-a[i].y)*(a[nxet].x-a[i].x)){
            now=nxet;
            nxet=now%N+1;
        }
        ans=max({ans,dist(a[i],a[now]),dist(a[i+1],a[now])});
    }
    printf("%.10lf",ans);
    return 0;
}