program abc(input,output);
var a:integer;
    b:longint;
  function fuc(x:integer):longint;
  begin
    if(x=2)
      then
        fuc:=3
      else
        fuc:=fuc(x-1)*2+1;
  end;
begin
  a:=30;
  b:=fuc(a);
  writeln(b);
end.