(use scheme.base)
(use scheme.read)
(use scheme.write)


(define yuki2749
  (let*
    (
      (n (read))
    )
    (cond
      ((= n 1)
        (display "1\n")
      )
      ((= n 2)
        (display "3\n")
      )
      (else
        (begin
          (write
            (let loop
              (
                (i 2)
                (a 1)
                (b 1)
              )
              (if (zero? (modulo b n))
                i
                (loop (+ i 1) b (+ a b))
              )
            )
          )
          (display "\n")
        )
      )
    )
  )
)