#include <iostream>#include <cmath>#define Pi acos(-1.0)using namespace std;int main(){ int t, a, b; int i; double x[4], y[4]; double p, q, ans, c1, c2, ang, l; while (scanf("%d%d%d", &t, &a, &b) && t) { for (i=0; i<3; i++) scanf("%lf%lf", &x[i], &y[i]); ang = atan2(y[0], x[0]) + a*2.0*Pi/t; l = sqrt(x[0]*x[0] + y[0]*y[0]); x[0] = l*cos(ang); y[0] = l*sin(ang); ang = atan2(y[2], x[2]) - b*2.0*Pi/t; l = sqrt(x[2]*x[2] + y[2]*y[2]); x[2] = l*cos(ang); y[2] = l*sin(ang); c1 = (x[0]*x[0] + y[0]*y[0] - x[1]*x[1] - y[1]*y[1])/2; c2 = (x[0]*x[0] + y[0]*y[0] - x[2]*x[2] - y[2]*y[2])/2; p = (c1*(y[0]-y[2])-c2*(y[0]-y[1]))/((x[0]-x[1])*(y[0]-y[2])-(x[0]-x[2])*(y[0]-y[1])); q = (c1*(x[0]-x[2])-c2*(x[0]-x[1]))/((y[0]-y[1])*(x[0]-x[2])-(y[0]-y[2])*(x[0]-x[1])); ans = sqrt(p*p + q*q); printf("%.0lfn", ans); } return 0;}
