#include <iostream>
#include <math.h>
using namespace std;

typedef long double ld;
ld PI = 4*atan(ld(1));

void rotate(ld &x, ld &y, ld angle) {
  ld x2 = x*cos(angle) - y*sin(angle);
  ld y2 = x*sin(angle) + y*cos(angle);
  x = x2;
  y = y2;
}

ld intersect(ld x1, ld y1, ld dx1, ld dy1, ld x2, ld y2, ld dx2, ld dy2)
{
  ld nx2 = -dy2;
  ld ny2 = dx2;
  ld dot2 = x2*nx2 + y2*ny2;
  ld k = (dot2 - (x1*nx2+y1*ny2)) / (dx1*nx2+dy1*ny2);
  x1 += k*dx1;
  y1 += k*dy1;
  return sqrt(x1*x1+y1*y1);
}

int solve(ld x1, ld y1, ld x2, ld y2, ld x3, ld y3) {
  ld xm1 = (x1+x2)/2;
  ld ym1 = (y1+y2)/2;
  ld xm2 = (x2+x3)/2;
  ld ym2 = (y2+y3)/2;
  ld yd1 = -(x2-x1)/2;
  ld xd1 = (y2-y1)/2;
  ld yd2 = -(x3-x2)/2;
  ld xd2 = (y3-y2)/2;
  return int(intersect(xm1, ym1, xd1, yd1, xm2, ym2, xd2, yd2)+0.5);
}

int main() {
  int t, k1, k2;
  ld x1, y1, x2, y2, x3, y3;
  while (1) {
    cin >> t >> k1 >> k2;
    if (t == 0)
      return 0;

    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
    rotate(x2, y2, -2*PI*ld(k1)/t);
    rotate(x3, y3, -2*PI*ld(k1+k2)/t);
    cout << solve(x1, y1, x2, y2, x3, y3) << endl;
  }
}