#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<algorithm>
#include<cstring>
using namespace std;
#define maxn 1005
int x,y;
int n;
long long area(int i)
{
int j=(i-1+n)%n,k=(i+1)%n;
long long x1=x-x,y1=y-y,
x2=x-x,y2=y-y;
return abs(x1*y2-x2*y1);
}
double length(int i)
{
int j=(i-1+n)%n,k=(i+1)%n;
long...