#include <bits/stdc++.h>
using namespace std;
int n;
struct point{
    long long x,y;
};
point A[102];
long long ccw(point a,point b,point c)
{
    long long ans=0;
    ans+=(a.x-b.x)*(a.y+b.y);
    ans+=(b.x-c.x)*(b.y+c.y);
    ans+=(c.x-a.x)*(c.y+a.y);
    if (ans<0) return -1;
    if (ans==0) return 0;
    if (ans>0) return 1;
}
long long tich(point a,point b)
{
    long long ans=(a.x-b.x)*(a.y+b.y);
    return ans;
}
int kt;
int check(int l,int r)
{
    for (int i=l+1;i<=r-1;i++)
        if (ccw(A[l],A[i],A[r])==0&&((A[l].x-A[i].x)*(A[r].x-A[i].x)<0||(A[l].y-A[i].y)*(A[r].y-A[i].y)<0)) return 0;
    for (int i=l+2;i<=r-1;i++)
        if (ccw(A[l],A[i-1],A[r])*ccw(A[l],A[i],A[r])<=0&&ccw(A[i-1],A[l],A[r])*ccw(A[i-1],A[r],A[i])<=0)
            return 0;
    return 1;
}
long long s=0;

void solve()
{
    cin>>n;
    for (int i=1;i<=n;i++)
    {
        cin>>A[i].x>>A[i].y;
        if (i>1) s+=tich(A[i-1],A[i]);
    }
    s+=tich(A[n],A[1]);
    if (s>0) kt=1;
    else kt=-1;
        long long res=1e18;
    for (int i=1;i<n;i++)
    {
        long long t=0;
        long long p=s;
        for (int j=i+1;j<=n;j++)
        {

            p-=tich(A[j-1],A[j]);
            t+=tich(A[j-1],A[j]);
            long long ss=t+tich(A[j],A[i]);
            long long pp=p+tich(A[i],A[j]);
            if (check(i,j)) res=min(res,abs(ss-pp));
           // cout<<i<<' '<<j<<' '<<t<<' '<<ss<<' '<<pp<<endl;
        }
    }
    double rr=double(res)/2;
    cout<<fixed<<setprecision(1)<<rr;
}
int main()
{
    freopen("poly.inp","r",stdin);
    freopen("poly.out","w",stdout);
    solve();
}