function nvar = p20_nvar ( option )

%*****************************************************************************80
%
%% P20_NVAR sets the number of variables for problem 20.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    14 October 2008
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, integer OPTION, the option chosen for this problem.
%    For some problems, several options are available.  At least,
%    OPTION = 1 is always legal.
%
%    Output, integer NVAR, the number of variables.
%
  nvar = 4;

  return
end