;; -*- coding: utf-8 -*-
(eval-when (:compile-toplevel :load-toplevel :execute)
  (sb-int:defconstant-eqx OPT
    #+swank '(optimize (speed 3) (safety 2))
    #-swank '(optimize (speed 3) (safety 0) (debug 0))
    #'equal)
  #+swank (ql:quickload '(:cl-debug-print :fiveam) :silent t)
  #-swank (set-dispatch-macro-character
           #\# #\> (lambda (s c p) (declare (ignore c p)) (read s nil nil t))))
#+swank (cl-syntax:use-syntax cl-debug-print:debug-print-syntax)
#-swank (disable-debugger) ; for CS Academy

;; BEGIN_INSERTED_CONTENTS
(declaim (ftype (function * (values fixnum &optional)) read-fixnum))
(defun read-fixnum (&optional (in *standard-input*))
  (declare #.OPT)
  (macrolet ((%read-byte ()
               `(the (unsigned-byte 8)
                     #+swank (char-code (read-char in nil #\Nul))
                     #-swank (sb-impl::ansi-stream-read-byte in nil #.(char-code #\Nul) nil))))
    (let* ((minus nil)
           (result (loop (let ((byte (%read-byte)))
                           (cond ((<= 48 byte 57)
                                  (return (- byte 48)))
                                 ((zerop byte) ; #\Nul
                                  (error "Read EOF or #\Nul."))
                                 ((= byte #.(char-code #\-))
                                  (setf minus t)))))))
      (declare ((integer 0 #.most-positive-fixnum) result))
      (loop
        (let* ((byte (%read-byte)))
          (if (<= 48 byte 57)
              (setq result (+ (- byte 48)
                              (* 10 (the (integer 0 #.(floor most-positive-fixnum 10)) result))))
              (return (if minus (- result) result))))))))

(defmacro dbg (&rest forms)
  #+swank
  (if (= (length forms) 1)
      `(format *error-output* "~A => ~A~%" ',(car forms) ,(car forms))
      `(format *error-output* "~A => ~A~%" ',forms `(,,@forms)))
  #-swank (declare (ignore forms)))

(defmacro define-int-types (&rest bits)
  `(progn
     ,@(mapcar (lambda (b) `(deftype ,(intern (format nil "UINT~A" b)) () '(unsigned-byte ,b))) bits)
     ,@(mapcar (lambda (b) `(deftype ,(intern (format nil "INT~A" b)) () '(signed-byte ,b))) bits)))
(define-int-types 2 4 7 8 15 16 31 32 62 63 64)

(declaim (inline println))
(defun println (obj &optional (stream *standard-output*))
  (let ((*read-default-float-format* 'double-float))
    (prog1 (princ obj stream) (terpri stream))))

(defconstant +mod+ 1000000007)

;;;
;;; Body
;;;

(defun main ()
  (declare #.OPT)
  (let* ((l (read))
         (dp (make-array '(200001 5) :element-type 'uint62 :initial-element 0))
         (as (make-array l :element-type 'uint32)))
    (declare (uint31 l))
    (dotimes (i l)
      (setf (aref as i) (read-fixnum)))
    (loop for x from 1 to l
          for base = (array-row-major-index dp x 0)
          for base-1 = (array-row-major-index dp (- x 1) 0)
          for prev of-type uint62 = (row-major-aref dp base-1)
          do (setf (row-major-aref dp base)
                   (+ prev (aref as (- x 1))))
             (setq prev (min prev (row-major-aref dp (+ base-1 1))))
             (setf (row-major-aref dp (+ base 1))
                   (+ prev
                      (if (evenp (aref as (- x 1)))
                          (if (zerop (aref as (- x 1)))
                              2
                              0)
                          1)))
             (setq prev (min prev (row-major-aref dp (+ base-1 2))))
             (setf (row-major-aref dp (+ base 2))
                   (+ prev
                      (if (oddp (aref as (- x 1))) 0 1)))
             (setq prev (min prev (row-major-aref dp (+ base-1 3))))
             (setf (row-major-aref dp (+ base 3))
                   (+ prev
                      (if (evenp (aref as (- x 1)))
                          (if (zerop (aref as (- x 1)))
                              2
                              0)
                          1)))
             (setq prev (min prev (row-major-aref dp (+ base-1 4))))
             (setf (row-major-aref dp (+ base 4))
                   (+ prev
                      (aref as (- x 1)))))
    (println (min (aref dp l 0)
                  (aref dp l 1)
                  (aref dp l 2)
                  (aref dp l 3)
                  (aref dp l 4)))))

#-swank (main)


Measured memory_bytes: 49256