#include <cstdlib>
#include <iostream>
#include <cmath>

using namespace std;

int main()
{ const int n=5;
  int x[n], y[n], d=0, max=0, p, q, k;
  bool m=true, l=r=false;
  cout<<"Vvedite"<<n<<" koordinat vershin\n";
  for (int i=0; i<n; i++)
  {
        cin>>x[i];
        cin>>y[i];
  }
cout<<"Vvedite p\n";
cin>>p;
for (i=0; i<n; i++)
{q=(p-x[i])*(y[i+1]-y[i])/(x[i+1]-x[i])-y[i];
if (y[i]>=q)
l=true;
if (y[i]<=q)
r=true;
for(k=1; k<n; k++)
{
if ((y[k]>q&&(r))||(y[k]<q&&(l)))
m=false;
}
}
if (m)
{
 for (int i=0; i<n; i++)
  {
        for (int j=1; j<n; j++)
        if (j>i)
          {
                d=sqrt(powl(x[i]-x[j],2)+powl(y[i]-y[j],2));
                if (d>max) max=d;
          }
  }
   cout<<"max= "<<max<<endl;
}
else
cout<<"Invalid data\n";
    system("PAUSE");
    return 0;
}