(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
           ;; enclose the form with VALUES to avoid being captured by LOOP macro
           #\# #\> (lambda (s c p) (declare (ignore c p)) `(values ,(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 (inline power-mod))
(defun power-mod (base power modulus)
  "BASE := integer
POWER, MODULUS := non-negative fixnum"
  (declare ((integer 0 #.most-positive-fixnum) modulus power)
           (integer base))
  (labels ((recur (x p)
             (declare ((integer 0 #.most-positive-fixnum) x p)
                      (values (integer 0 #.most-positive-fixnum)))
             (cond ((zerop p) 1)
                   ((evenp p) (recur (mod (* x x) modulus) (ash p -1)))
                   (t (mod (* x (recur x (- p 1))) modulus)))))
    (recur (mod base modulus) power)))

;;;
;;; Arithmetic operations with static modulus
;;;

;; FIXME: Currently MOD* and MOD+ doesn't apply MOD when the number of
;; parameters is one.
(defmacro define-mod-operations (divisor)
  `(progn
     (defun mod* (&rest args)
       (reduce (lambda (x y) (mod (* x y) ,divisor)) args))

     (sb-c:define-source-transform mod* (&rest args)
       (if (null args)
           1
           (reduce (lambda (x y) `(mod (* ,x ,y) ,',divisor)) args)))

     (defun mod+ (&rest args)
       (reduce (lambda (x y) (mod (+ x y) ,divisor)) args))

     (sb-c:define-source-transform mod+ (&rest args)
       (if (null args)
           0
           (reduce (lambda (x y) `(mod (+ ,x ,y) ,',divisor)) args)))

     (define-modify-macro incfmod (delta)
       (lambda (x y) (mod (+ x y) ,divisor)))

     (define-modify-macro decfmod (delta)
       (lambda (x y) (mod (- x y) ,divisor)))

     (define-modify-macro mulfmod (multiplier)
       (lambda (x y) (mod (* x y) ,divisor)))))

;;;
;;; Modular arithmetic
;;;

;; Blankinship algorithm
;; Reference: https://topcoder.g.hatena.ne.jp/spaghetti_source/20130126/1359171466 (Japanese)
(declaim (ftype (function * (values fixnum fixnum &optional)) %ext-gcd))
(defun %ext-gcd (a b)
  (declare (optimize (speed 3) (safety 0))
           (fixnum a b))
  (let ((y 1)
        (x 0)
        (u 1)
        (v 0))
    (declare (fixnum y x u v))
    (loop (when (zerop a)
            (return (values x y)))
          (let ((q (floor b a)))
            (decf x (the fixnum (* q u)))
            (rotatef x u)
            (decf y (the fixnum (* q v)))
            (rotatef y v)
            (decf b (the fixnum (* q a)))
            (rotatef b a)))))

;; recursive version
;; (defun %ext-gcd (a b)
;;   (declare (optimize (speed 3) (safety 0))
;;            (fixnum a b))
;;   (if (zerop b)
;;       (values 1 0)
;;       (multiple-value-bind (p q) (floor a b) ; a = pb + q
;;         (multiple-value-bind (v u) (%ext-gcd b q)
;;           (declare (fixnum u v))
;;           (values u (the fixnum (- v (the fixnum (* p u)))))))))

;; TODO: deal with bignums
(declaim (inline ext-gcd))
(defun ext-gcd (a b)
  "Returns two integers X and Y which satisfy AX + BY = gcd(A, B)."
  (declare ((integer #.(- most-positive-fixnum) #.most-positive-fixnum) a b))
  (if (>= a 0)
      (if (>= b 0)
          (%ext-gcd a b)
          (multiple-value-bind (x y) (%ext-gcd a (- b))
            (declare (fixnum x y))
            (values x (- y))))
      (if (>= b 0)
          (multiple-value-bind (x y) (%ext-gcd (- a) b)
            (declare (fixnum x y))
            (values (- x) y))
          (multiple-value-bind (x y) (%ext-gcd (- a) (- b))
            (declare (fixnum x y))
            (values (- x) (- y))))))

(declaim (inline mod-inverse)
         (ftype (function * (values (mod #.most-positive-fixnum) &optional)) mod-inverse))
;; (defun mod-inverse (a modulus)
;;   "Solves ax ≡ 1 mod m. A and M must be coprime."
;;   (declare (integer a)
;;            ((integer 1 #.most-positive-fixnum) modulus))
;;   (mod (%ext-gcd (mod a modulus) modulus) modulus))

(defun mod-inverse (a modulus)
  (declare ((integer 1 #.most-positive-fixnum) modulus))
  (let ((a (mod a modulus))
        (b modulus)
        (u 1)
        (v 0))
    (declare (fixnum a b u v))
    (loop until (zerop b)
          for quot = (floor a b)
          do (decf a (the fixnum (* quot b)))
             (rotatef a b)
             (decf u (the fixnum (* quot v)))
             (rotatef u v))
    (setq u (mod u modulus))
    (if (< u 0)
        (+ u modulus)
        u)))

;; not tested
;; TODO: move to another file
(declaim (inline binomial))
(defun mod-binomial (n k modulus)
  (declare ((integer 0 #.most-positive-fixnum) modulus))
  (if (or (< n k) (< n 0) (< k 0))
      0
      (let ((k (if (< k (- n k)) k (- n k)))
            (num 1)
            (denom 1))
        (declare ((integer 0) k num denom))
        (loop for x from n above (- n k)
              do (setq num (mod (* num x) modulus)))
        (loop for x from 1 to k
              do (setq denom (mod (* denom x) modulus)))
        (mod (* num (mod-inverse denom modulus)) modulus))))

(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
;;;

(define-mod-operations +mod+)
(defun main ()
  (let* ((n (read))
         (a (read))
         (b (read)))
    (println (mod+ (power-mod 2 n +mod+)
                   (- (mod-binomial n a +mod+))
                   (- (mod-binomial n b +mod+))
                   -1))))

#-swank (main)

;;;
;;; Test and benchmark
;;;

#+swank
(defun io-equal (in-string out-string &key (function #'main) (test #'equal))
  "Passes IN-STRING to *STANDARD-INPUT*, executes FUNCTION, and returns true if
the string output to *STANDARD-OUTPUT* is equal to OUT-STRING."
  (labels ((ensure-last-lf (s)
             (if (eql (uiop:last-char s) #\Linefeed)
                 s
                 (uiop:strcat s uiop:+lf+))))
    (funcall test
             (ensure-last-lf out-string)
             (with-output-to-string (out)
               (let ((*standard-output* out))
                 (with-input-from-string (*standard-input* (ensure-last-lf in-string))
                   (funcall function)))))))

#+swank
(defun get-clipbrd ()
  (with-output-to-string (out)
    (run-program "powershell.exe" '("-Command" "Get-Clipboard") :output out :search t)))

#+swank (defparameter *this-pathname* (uiop:current-lisp-file-pathname))
#+swank (defparameter *dat-pathname* (uiop:merge-pathnames* "test.dat" *this-pathname*))

#+swank
(defun run (&optional thing (out *standard-output*))
  "THING := null | string | symbol | pathname

null: run #'MAIN using the text on clipboard as input.
string: run #'MAIN using the string as input.
symbol: alias of FIVEAM:RUN!.
pathname: run #'MAIN using the text file as input."
  (let ((*standard-output* out))
    (etypecase thing
      (null
       (with-input-from-string (*standard-input* (delete #\Return (get-clipbrd)))
         (main)))
      (string
       (with-input-from-string (*standard-input* (delete #\Return thing))
         (main)))
      (symbol (5am:run! thing))
      (pathname
       (with-open-file (*standard-input* thing)
         (main))))))

#+swank
(defun gen-dat ()
  (uiop:with-output-file (out *dat-pathname* :if-exists :supersede)
    (format out "")))

#+swank
(defun bench (&optional (out (make-broadcast-stream)))
  (time (run *dat-pathname* out)))

;; To run: (5am:run! :sample)
#+swank
(it.bese.fiveam:test :sample
  (it.bese.fiveam:is
   (common-lisp-user::io-equal "4 1 3
"
    "7
"))
  (it.bese.fiveam:is
   (common-lisp-user::io-equal "1000000000 141421 173205
"
    "34076506
")))


Measured memory_bytes: 31080