program fenlie;
var
  f:array[0..1,1..10000]of int64;
  i,j,n,x,y:longint;
  ans:int64;
begin
  assign (input,'mushroom.in');
  reset (input);
  assign (output,'mushroom.out');
  rewrite (output);
    readln(n);
    f[1,2]:=1;
    for i:=2 to n do
    begin
      if i mod 2=0 then
      begin
        y:=0;
        x:=1
      end
      else
      begin
        y:=1;
        x:=0
      end;
      f[y,1]:=f[x,2];;
      for j:=2 to i do
      begin
        f[y,j]:=f[x,j-1]+f[x,j+1];
      end;
      f[y,i+1]:=f[x,i];
    end;
    for i:=1 to n+1 do
      ans:=ans+f[n mod 2,i];
    writeln(ans);
  close (input);
  close(output)
end.