// This program reads in the vertices of a polygon from standard
// input, and determines whether the vertices have been entered in
// cw or ccw order.  It finds the lowest and rightmost vertex, and
// computes the cross-product of the vectors along its incident
// edges.
// Written by Joseph O'Rourke, 25 August 1995.
// orourke@cs.smith.edu

#include <iostream.h>
#include <iomanip.h>
#include <stdlib.h>

#define NMAX 100  // Maximum number of polygon vertices
#define X 0
#define Y 1

int ReadPoly( void );
int FindLR( int n );
int Ccw( int n, int m );

int poly[NMAX][2];

int main() {
  int n, m;

  n = ReadPoly();
  m = FindLR( n );
  if ( Ccw( n, m ) == 1 )
    cout << "The polygon is oriented counterclockwise" << endl;
  else
    cout << "The polygon is oriented clockwise" << endl;
}

int ReadPoly()
{
  int i,n;

  i = 0;
  while( !cin.eof() ) {
    cin >> poly[i][X] >> poly[i][Y];
    i++;
  }
  n = i-1;
  // Echo polygon coordinates.
  cout <<  "n=" << n << " vertices read." << endl;
  for( i=0; i<n; i++ ) {
    cout << "i="   << setw(3) << i;
    cout << "; x=" << setw(3) << poly[i][X];
    cout << "; y=" << setw(3) << poly[i][Y] << endl;
  }
  return n;
}

// FindLR finds the lowest, rightmost vertex of poly.
int FindLR( int n )
{
  int i,m;
  int min[2];

  min[X] = poly[0][X];
  min[Y] = poly[0][Y];
  m = 0;

  cout << "FindLR:";
  for( i = 0; i < n; i++ ) {
    if( (poly[i][Y] < min[Y]) ||
        ( (poly[i][Y] == min[Y]) && (poly[i][X] > min[X]) )
      ) {
      m = i;
      min[X] = poly[m][X];
      min[Y] = poly[m][Y];
    }
    //cout << "i=" << i << " m=" << m;
  }
  cout << " min = " << min[X] << ", " << min[Y] << endl;
  return m;
}

int Ccw( int n, int m )
{
  int m1, area2;
  int i;
  int a[2], b[2], c[2]; //Just renaming

  m1 = (m + (n-1)) % n; //= m - 1
  //cout << "m=" << m << ", m1=" << m1 << endl;
  // assign a[0] to point to poly[m1][0] etc.
  for( i = 0; i < 2; i++ ) {
    a[i] = poly[m1][i];
    b[i] = poly[m][i];
    c[i] = poly[(m+1)%n][i];
  }

  area2 =
                a[0] * b[1] - a[1] * b[0] +
                a[1] * c[0] - a[0] * c[1] +
                b[0] * c[1] - c[0] * b[1];
  cout << "Ccw: area = " << area2 << endl;
  if ( area2 > 0 )
    return 1;
  else if ( area2 < 0 )
    return -1;
  else
    return 0;
}