;; -*- 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 (progn (ql:quickload '(:cl-debug-print :fiveam))
                 (shadow :run)
                 (use-package :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)

;; 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* ((n (read))
         (m (read))
         (ss (make-array n :element-type 'uint32))
         (ts (make-array m :element-type 'uint32))
         (dp (make-array (list (+ n 1) (+ m 1)) :element-type 'uint32 :initial-element 0))
         (cumul (make-array (list (+ n 1) (+ m 1)) :element-type 'uint32 :initial-element 0)))
    (declare (uint16 n m))
    (dotimes (i n)
      (setf (aref ss i) (read-fixnum)))
    (dotimes (j m)
      (setf (aref ts j) (read-fixnum)))
    (loop for x from 1 to n
          do (loop for y from 1 to m
                   do (when (= (aref ss (- x 1)) (aref ts (- y 1)))
                        (setf (aref dp x y)
                              (mod (+ 1 (aref cumul (- x 1) (- y 1))) +mod+)))
                      (setf (aref cumul x y)
                            (mod (+ (aref cumul (- x 1) y)
                                    (aref cumul x (- y 1))
                                    (- (aref cumul (- x 1) (- y 1)))
                                    (aref dp x y))
                                 +mod+))))
    (println (mod (+ 1 (aref cumul n m)) +mod+))))

#-swank(main)


Measured memory_bytes: 45540