;; -*- coding: utf-8 -*-
#-(or child-sbcl swank)
(quit
 :unix-status
 (process-exit-code
  (run-program *runtime-pathname*
               `("--control-stack-size" "32MB"
                 "--noinform" "--disable-ldb" "--lose-on-corruption" "--end-runtime-options"
                 "--eval" "(push :child-sbcl *features*)"
                 "--script" ,(namestring *load-pathname*))
               :output t :error t :input t)))

(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 (cl-syntax:use-syntax cl-debug-print:debug-print-syntax)

;; BEGIN_INSERTED_CONTENTS

(defmacro buffered-read-line (&optional (buffer-size 30) (in '*standard-input*) (terminate-char #\Space))
  "Note that the returned string will be reused."
  (let ((buffer (gensym))
        (character (gensym))
        (idx (gensym)))
    `(let ((,buffer (load-time-value (make-string ,buffer-size
                                                  :element-type 'base-char))))
       (declare (simple-base-string ,buffer))
       (loop for ,character of-type base-char =
                #-swank (code-char (read-byte ,in nil #.(char-code #\Newline)))
                #+swank (read-char ,in nil #\Newline)
             for ,idx from 0
             until (char= ,character #\Newline)
             do (setf (schar ,buffer ,idx) ,character)
             finally (when (< ,idx ,buffer-size)
                       (setf (schar ,buffer ,idx) ,terminate-char))
                     (return (values ,buffer ,idx))))))

(defmacro split-ints-bind (vars string &body body)
  (let ((position (gensym))
        (s (gensym)))
    (labels ((expand (vars &optional init-pos)
               (if (null vars)
                   body
                   `((multiple-value-bind (,(car vars) ,position)
                         (parse-integer ,s :start ,(or init-pos position)
                                           :junk-allowed t)
                       ,@(when (null (cdr vars)) `((declare (ignore ,position))))
                       ,@(expand (cdr vars)))))))
      `(let ((,s ,string))
         (declare (string ,s))
         ,@(expand vars 0)))))

(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)

(defmacro println (obj &optional (stream '*standard-output*))
  `(let ((*read-default-float-format* 'double-float))
     (prog1 (princ ,obj ,stream) (terpri ,stream))))

(defconstant +mod+ 1000000007)

;; Body

(declaim (ftype (function * (values (or null simple-bit-vector) &optional)) bipartite-p))
(defun bipartite-p (graph)
  "Decides if GRAPH is bipartite and returns the vector of colorings if
so. GRAPH must be a vector of adjacency lists."
  (declare #.OPT ((simple-array list (*)) graph))
  (let* ((n (length graph))
         (visited (make-array n :element-type 'bit :initial-element 0))
         (colors (make-array n :element-type ' bit :initial-element 0)))
    (labels ((dfs (vertex color)
               (cond ((zerop (aref visited vertex))
                      (setf (aref visited vertex) 1
                            (aref colors vertex) color)
                      (if (= color 1)
                          (dolist (neighbor (aref graph vertex))
                            (dfs neighbor 0))
                          (dolist (neighbor (aref graph vertex))
                            (dfs neighbor 1))))
                     ((/= color (aref colors vertex))
                      (return-from bipartite-p nil)))))
      (dotimes (i n colors)
        (when (zerop (aref visited i))
          (dfs i 1))))))

(defun main ()
  (declare #.OPT)
  (let* ((n (read))
         (m (read))
         (graph (make-array n :element-type 'list :initial-element nil)))
    (declare (uint31 n m))
    (dotimes (i m)
      (split-ints-bind (a b) (buffered-read-line 13)
        (declare (uint31 a b))
        (push (- b 1) (aref graph (- a 1)))
        (push (- a 1) (aref graph (- b 1)))))
    (let ((colors (bipartite-p graph)))
      (println
       (if colors
           (- (* (count 1 colors) (count 0 colors)) m)
           (- (ash (* n (- n 1)) -1) m))))))

#-swank(main)


Measured memory_bytes: 29628