#include<bits/stdc++.h>

typedef long long i64;

typedef double ld;

struct pos{

    int x,y;

    ld abs(){return sqrt(i64(x)*x+i64(y)*y);}

}ps[];

pos operator-(const pos&a,const pos&b){return (pos){a.x-b.x,a.y-b.y};}

i64 operator*(const pos&a,const pos&b){return i64(a.x)*b.y-i64(a.y)*b.x;}

int sgn(i64 x){return x<?-:x>;}

int n,t[],kp;

ld ans=,ks[];

void maxs(ld&x,ld y){if(x<y)x=y;}

#define F(a) ps[a]*ps[a+1]/ld(p*(ps[a+1]-ps[a]))*pl

void chk(pos p){

    kp=;

    ld pl=p.abs();

    for(int i=;i<n+;++i)t[i]=sgn(p*ps[i]);

    for(int i=,z;i<n;++i)if(t[i]&&t[i]!=t[i+]){

        for(z=i+;!t[z];++z);

        if(t[z]!=t[i]){

            if(z-i<)ks[kp++]=F(i);

            else{

                ld a0=F(i),a1=F(z-);

                ks[kp++]=(a0<a1)==(t[i]>)?a0:a1;

            }

        }else if(z-i==){

            ld a0=F(i),a1=F(z-);

            if((a0<a1)==(t[i]>))maxs(ans,fabs(a1-a0));

        }

    }

    std::sort(ks,ks+kp);

    for(int i=;i<kp;i+=)maxs(ans,ks[i+]-ks[i]);

}

int main(){

    scanf("%d",&n);

    for(int i=;i<n;++i)scanf("%d%d",&ps[i].x,&ps[i].y);

    for(int i=;i<n;++i){

        pos o=ps[i];

        for(int j=;j<n;++j)ps[j]=ps[j]-o;

        for(int j=;j<;++j)ps[n+j]=ps[j];

        for(int j=i+;j<n;++j)chk(ps[j]);

    }

    printf("%.8f",ans);

    return ;

}