(define (main args)
  (let* ([n (read)]
         [mv (vector-tabulate (+ n 1) identity)])
    (let loop ([k 2]
               [c 3]
               [i 3])
      (cond [(> c n) #t]
            [(> i n) (loop (+ k 1) (quotient (* (+ k 1) (+ k 2)) 2) (quotient (* (+ k 1) (+ k 2)) 2))]
            [else (vector-set! mv i (min (vector-ref mv i) (+ 1 (vector-ref mv (- i c)))))
                  (loop k c (+ i 1))]))
    (print (vector-ref mv n))
    )
  0)