#include <iostream>
#include <cmath>
using namespace std;

void Rotate(double x, double y, double &xx, double &yy, double t)
{
  xx =   x * cos(t) + y * sin(t);
  yy = - x * sin(t) + y * cos(t);
}

double Det(double m[2][2])
{
  return m[0][0] * m[1][1] - m[0][1] * m[1][0];
}

double Det(double m[3][3])
{
  double m2[2][2];
  double total = 0.0;

  m2[0][0] = m[1][1];
  m2[0][1] = m[1][2];
  m2[1][0] = m[2][1];
  m2[1][1] = m[2][2];
  total += m[0][0] * Det(m2);

  m2[0][0] = m[0][1];
  m2[0][1] = m[0][2];
  m2[1][0] = m[2][1];
  m2[1][1] = m[2][2];
  total -= m[1][0] * Det(m2);

  m2[0][0] = m[0][1];
  m2[0][1] = m[0][2];
  m2[1][0] = m[1][1];
  m2[1][1] = m[1][2];
  total += m[2][0] * Det(m2);
  
  return total;
}

void Center(double x[3], double y[3], double &cx, double &cy)
{
  double m1[3][3];
  m1[0][0] = x[0]*x[0] + y[0]*y[0];
  m1[1][0] = y[0];
  m1[2][0] = 1;
  m1[0][1] = x[1]*x[1] + y[1]*y[1];
  m1[1][1] = y[1];
  m1[2][1] = 1;
  m1[0][2] = x[2]*x[2] + y[2]*y[2];
  m1[1][2] = y[2];
  m1[2][2] = 1;

  double m2[3][3];
  m2[0][0] = x[0];
  m2[1][0] = x[0]*x[0] + y[0]*y[0];
  m2[2][0] = 1;
  m2[0][1] = x[1];
  m2[1][1] = x[1]*x[1] + y[1]*y[1];
  m2[2][1] = 1;
  m2[0][2] = x[2];
  m2[1][2] = x[2]*x[2] + y[2]*y[2];
  m2[2][2] = 1;

  double m3[3][3];
  m3[0][0] = x[0];
  m3[0][1] = y[0];
  m3[0][2] = 1.0;
  m3[1][0] = x[1];
  m3[1][1] = y[1];
  m3[1][2] = 1.0;
  m3[2][0] = x[2];
  m3[2][1] = y[2];
  m3[2][2] = 1.0;

  cx = Det(m1) / (2.0 * Det(m3));
  cy = Det(m2) / (2.0 * Det(m3));
}


int T, k1, k2;
double ox[3], oy[3];
double rx[3], ry[3];

int main()
{
  while (true)
  {
    cin >> T;
    cin >> k1;
    cin >> k2;
    if ((T == 0) && (k1 == 0) && (k2 == 0))
      break;

    for (int i = 0; i < 3; ++i)
    {
      cin >> ox[i];
      cin >> oy[i];
    }
    
    Rotate(ox[0], oy[0], rx[0], ry[0], 0.0);
    Rotate(ox[1], oy[1], rx[1], ry[1], 2.0*M_PI/double(T) * double(k1));
    Rotate(ox[2], oy[2], rx[2], ry[2], 2.0*M_PI/double(T) * double(k1 + k2));

    double cx, cy;
    Center(rx, ry, cx, cy);
    double R = sqrt(cx*cx + cy*cy);
    double Ri = int(floor(R + 0.5));
    cout << Ri << endl;
    
  }
  return 0;
}