#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[211];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<0?-1:x>0;}int n,t[211],kp;ld ans=0,ks[211];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]))*plvoid chk(pos p){    kp=0;    ld pl=p.abs();    for(int i=0;i<n+5;++i)t[i]=sgn(p*ps[i]);    for(int i=0,z;i<n;++i)if(t[i]&&t[i]!=t[i+1]){        for(z=i+1;!t[z];++z);        if(t[z]!=t[i]){            if(z-i<3)ks[kp++]=F(i);            else{                ld a0=F(i),a1=F(z-1);                ks[kp++]=(a0<a1)==(t[i]>0)?a0:a1;            }        }else if(z-i==3){            ld a0=F(i),a1=F(z-1);            if((a0<a1)==(t[i]>0))maxs(ans,fabs(a1-a0));        }    }    std::sort(ks,ks+kp);    for(int i=0;i<kp;i+=2)maxs(ans,ks[i+1]-ks[i]);}int main(){    scanf("%d",&n);    for(int i=0;i<n;++i)scanf("%d%d",&ps[i].x,&ps[i].y);    for(int i=0;i<n;++i){        pos o=ps[i];        for(int j=0;j<n;++j)ps[j]=ps[j]-o;        for(int j=0;j<5;++j)ps[n+j]=ps[j];        for(int j=i+1;j<n;++j)chk(ps[j]);    }    printf("%.8f",ans);    return 0;}