Mid-USA'1997的标程，是用Pascal语言写的。

program skew_binary;

var
  skew: string;


function digit (c: char): longint;
begin
  case c of
    '0': digit := 0;
    '1': digit := 1;
    '2': digit := 2;
  end
end;


function translate (s: string): longint;
var
  i: integer;
  n: longint;
  power_of_2: longint;
begin
  n := 0;
  power_of_2 := 2;
  for i := length(s) downto 1 do begin
    n := n + digit(s[i])*(power_of_2 - 1);
    power_of_2 := power_of_2 * 2;
  end;
  translate := n;
end;


begin
  repeat
    readln (skew);
    if skew <> '0' then writeln (translate (skew));
  until skew = '0';
end.