program mushroom;
var
  i,j,na,nb,n:longint;
  a,b,t:array[1..10000000]of longint;
begin
  assign(input,'mushroom.in');
  reset(input);
  assign(output,'mushroom.out');
  rewrite(output);
  read(n);
  na:=1;
  a[1]:=2;
  for j:=1 to n-1 do
  begin
    nb:=0;
    fillchar(t,sizeof(t),0);
    for i:=1 to na do
      if a[i]=1 then
      begin
        inc(nb);
      	b[nb]:=2
      end
      else
      begin
        inc(nb); b[nb]:=a[i]-1;
      	inc(nb); b[nb]:=a[i]+1
      end;
    for i:=1 to nb do
      a[i]:=b[i];
    na:=nb;
  end;
  writeln(na) ;
  close(input);
  close(output)
end.