program fibo;



function fib(N : cardinal) : cardinal;
begin
  if N < 2 then fib := 1
  else fib := fib(N-2) + fib(N-1);
End;

var NUM, code : integer;
begin
  NUM :=1;
  if ParamCount=1 then
    Val(ParamStr(1),NUM,code);

  WriteLn(fib(NUM));
end.