#-swank
(unless (member :child-sbcl *features*)
  (quit
   :unix-status
   (process-exit-code
    (run-program *runtime-pathname*
                 `("--control-stack-size" "64MB"
                   "--noinform" "--disable-ldb" "--lose-on-corruption" "--end-runtime-options"
                   "--eval" "(push :child-sbcl *features*)"
                   "--script" ,(namestring *load-pathname*))
                 :output t :error t :input t))))

;; -*- 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))
         (coord-x (make-array 100001 :element-type 'list :initial-element nil))
         (coord-y (make-array 100001 :element-type 'list :initial-element nil))
         (points-x (make-array n :element-type 'uint32))
         (points-y (make-array n :element-type 'uint32)))
    (dotimes (i n)
      (let ((x (read-fixnum))
            (y (read-fixnum)))
        (setf (aref points-x i) x
              (aref points-y i) y)
        (push i (aref coord-x x))
        (push i (aref coord-y y))))
    (let ((groups (make-array n :element-type 'int32 :initial-element -1))
          (groups-sizes (make-array n :element-type 'uint32 :initial-element 0))
          (groups-xs (make-array n :element-type 'uint32))
          (groups-ys (make-array n :element-type 'uint32))
          (table-xs (make-hash-table :test #'eq))
          (table-ys (make-hash-table :test #'eq))
          (current 0))
      (declare (uint32 current))
      (labels ((dfs (v)
                 (setf (aref groups v) current)
                 (setf (gethash (aref points-x v) table-xs) t)
                 (setf (gethash (aref points-y v) table-ys) t)
                 (incf (aref groups-sizes current))
                 (dolist (neighbor (aref coord-x (aref points-x v)))
                   (when (= -1 (aref groups neighbor))
                     (dfs neighbor)))
                 (dolist (neighbor (aref coord-y (aref points-y v)))
                   (when (= -1 (aref groups neighbor))
                     (dfs neighbor)))))
        (dotimes (i n)
          (when (= -1 (aref groups i))
            (clrhash table-xs)
            (clrhash table-ys)
            (dfs i)
            (setf (aref groups-xs current) (hash-table-count table-xs))
            (setf (aref groups-ys current) (hash-table-count table-ys))
            (incf current)))
        groups)
      (let ((group-count (+ 1 (reduce #'max groups)))
            (res 0))
        (declare (uint62 res group-count))
        (dotimes (g group-count)
          (let ((num-xs (aref groups-xs g))
                (num-ys (aref groups-ys g)))
            (declare (uint31 num-xs num-ys))
            (incf res (- (* num-xs num-ys) (aref groups-sizes g)))))
        (println res)))))

#-swank(main)


Measured memory_bytes: 54324