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

;; BEGIN_INSERTED_CONTENTS
(declaim (inline delete-adjacent-duplicates))
(defun delete-adjacent-duplicates (seq &key (test #'eql))
  "Destructively deletes adjacent duplicates of SEQ: e.g. #(1 1 1 2 2 1 3) ->
#(1 2 1 3)"
  (declare (sequence seq)
           (function test))
  (etypecase seq
    (vector
     (if (zerop (length seq))
         seq
         (let ((prev (aref seq 0))
               (end 1))
           (loop for pos from 1 below (length seq)
                 unless (funcall test prev (aref seq pos))
                 do (setf prev (aref seq pos)
                          (aref seq end) (aref seq pos)
                          end (+ 1 end)))
           (if (array-has-fill-pointer-p seq)
               (adjust-array seq end :fill-pointer end)
               (adjust-array seq end)))))
    (list
     (loop for rest on seq
           unless (and (cdr rest)
                       (funcall test (first rest) (second rest)))
           collect (car rest)))))

(defun map-run-length (function seq &key (test #'eql))
  "Applies FUNCTION to each equal successive element of SEQ. FUNCTION must take
two arguments: the first one receives an element in SEQ and the second one
receives the number of the successive elements equal to the first.

Example: (map-run-length (lambda (x c) (format t \"~D ~D~%\" x c)) #(1 1 1 2 2 1 3))
1 3
2 2
1 1
3 1
"
  (declare (sequence seq)
           (function test function))
  (etypecase seq
    (vector
     (unless (zerop (length seq))
       (let ((prev (aref seq 0))
             (start 0))
         (loop for pos from 1 below (length seq)
               unless (funcall test prev (aref seq pos))
               do (funcall function prev (- pos start))
                  (setf prev (aref seq pos)
                        start pos)
               finally (funcall function prev (- pos start))))))
    (list
     (when (cdr seq)
       (labels ((recur (lst prev count)
                  (declare ((integer 0 #.most-positive-fixnum) count))
                  (cond ((null lst)
                         (funcall function prev count))
                        ((funcall test prev (car lst))
                         (recur (cdr lst) prev (+ 1 count)))
                        (t (funcall function prev count)
                           (recur (cdr lst) (car lst) 1)))))
         (recur (cdr seq) (car seq) 1))))))

(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 ()
  (let* ((s (concatenate 'simple-base-string (read-line) "0"))
         (n (- (length s) 1))
         (pos 0)
         (prevc #\1)
         (prevnum 0)
         (res 0)
         (last n))
    (loop for i from (- n 1) downto 0
          while (char= (aref s (- n 1)) (aref s i))
          do (setq last i))
    (loop (when (>= pos last)
            (multiple-value-bind (quot rem) (floor (- n pos) 3)
              (incf res (+ (* 2 quot) (if (zerop rem) 0 1))))
            (return))
          (incf res)
          (if (char= (aref s pos) prevc)
              (if (= prevnum 2)
                  (progn (setq prevc (aref s pos))
                         (setq prevnum 1)
                         (incf pos 1))
                  (progn (setq prevc (aref s (+ pos 1)))
                         (setq prevnum 2)
                         (incf pos 2)))
              (progn (setq prevc (aref s pos))
                     (setq prevnum 1)
                     (incf pos 1))))
    (println res)))

#-swank (main)



Measured memory_bytes: 26344