program Z1;

{$APPTYPE CONSOLE}

var
   Number: Int64;
   i: Byte;
   Num, Step: Word;
begin
   Num := 0;
   Step := 1;
   Readln(Number);
   while Number <> 0 do
   begin
      i := Number mod 2;
      Num := Num + i * Step;
      Step := Step * 2;
      Number := Number div 10;
   end;
   Writeln(Num);
   Readln;
end.