#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/ch_graham_andrew.h>
typedef K::Point_2 Point_2;
int main()
{
std::istream_iterator< Point_2 > in_start( std::cin );
std::istream_iterator< Point_2 > in_end;
std::ostream_iterator< Point_2 > out( std::cout, "\n" );
return 0;
}