var a,y,k,h:real;
begin
Readln(k,h);
y:=2;
  While y<=3 do
  begin
  a:=arccos(y/k);
  a:=RadToDeg(a);
  Writeln('Ïðè y = ',y,';   Óãîë a = ',a);
  y:=y+h;
  end;
end.