Problem:
Score : 300 points

Problem Statement

A programming competition site AtCode provides algorithmic problems.
Each problem is allocated a score based on its difficulty.
Currently, for each integer i between 1 and D (inclusive), there are p_i problems with a score of 100i points.
These p_1 + … + p_D problems are all of the problems available on AtCode.

A user of AtCode has a value called total score.
The total score of a user is the sum of the following two elements:

Base score: the sum of the scores of all problems solved by the user.

Perfect bonuses: when a user solves all problems with a score of 100i points, he/she earns the perfect bonus of c_i points, aside from the base score (1 ≤ i ≤ D).

Takahashi, who is the new user of AtCode, has not solved any problem.
His objective is to have a total score of G or more points.
At least how many problems does he need to solve for this objective?

Constraints

1 ≤ D ≤ 10

1 ≤ p_i ≤ 100

100 ≤ c_i ≤ 10^6

100 ≤ G

All values in input are integers.

c_i and G are all multiples of 100.

It is possible to have a total score of G or more points.

Input

Input is given from Standard Input in the following format:

D G
p_1 c_1
:
p_D c_D

Output

Print the minimum number of problems that needs to be solved in order to have a total score of G or more points. Note that this objective is always achievable (see Constraints).

Sample Input 1

2 700
3 500
5 800

Sample Output 1

3

In this case, there are three problems each with 100 points and five problems each with 200 points. The perfect bonus for solving all the 100-point problems is 500 points, and the perfect bonus for solving all the 200-point problems is 800 points. Takahashi's objective is to have a total score of 700 points or more.

One way to achieve this objective is to solve four 200-point problems and earn a base score of 800 points. However, if we solve three 100-point problems, we can earn the perfect bonus of 500 points in addition to the base score of 300 points, for a total score of 800 points, and we can achieve the objective with fewer problems.

Sample Input 2

2 2000
3 500
5 800

Sample Output 2

7

This case is similar to Sample Input 1, but the Takahashi's objective this time is 2000 points or more. In this case, we inevitably need to solve all five 200-point problems, and by solving two 100-point problems additionally we have the total score of 2000 points.

Sample Input 3

2 400
3 500
5 800

Sample Output 3

2

This case is again similar to Sample Input 1, but the Takahashi's objective this time is 400 points or more. In this case, we only need to solve two 200-point problems to achieve the objective.

Sample Input 4

5 25000
20 1000
40 1000
50 1000
30 1000
1 1000

Sample Output 4

66

There is only one 500-point problem, but the perfect bonus can be earned even in such a case.

Solution in Common Lisp (SBCL 1.1.14) (judge verdict: Accepted)

(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 nlet (name args &body body)
  (labels ((ensure-list (x) (if (listp x) x (list x))))
    (let ((args (mapcar #'ensure-list args)))
      `(labels ((,name ,(mapcar #'car args) ,@body))
         (,name ,@(mapcar #'cadr args))))))

(defmacro split-ints-and-bind (vars string &body body)
  (let ((pos1 (gensym "POS"))
	(pos2 (gensym "POS"))
	(str (gensym "STR")))
    (labels ((expand (vars &optional (init-pos1 t))
	       (if (null vars)
		   body
		   `((let* ((,pos1 ,(if init-pos1 0 `(1+ ,pos2)))
			    (,pos2 (position #\space ,str :start ,pos1 :test #'char=))
			    (,(car vars) (parse-integer ,str :start ,pos1 :end ,pos2)))
		       ,@(expand (cdr vars) nil))))))
      `(let ((,str ,string))
         (declare (string ,str))
	 ,@(expand vars)))))

(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))))

;; Hauptteil

(defun main ()
  (let* ((d (read))
         (required-score (floor (read) 100))
         (ps (make-array d :element-type 'uint32))
         (max-scores (make-array d :element-type 'uint32)))
    (dotimes (i d)
      (split-ints-and-bind (p c) (read-line)
        (setf (aref ps i) p
              (aref max-scores i) (+ (floor c 100) (* p (+ i 1))))))
    (let ((min-num most-positive-fixnum))
      (dotimes (bits (expt 2 d))
        (let ((num 0)
              (score 0))
          (dotimes (i d)
            (when (= 1 (ldb (byte 1 i) bits))
              (incf score (aref max-scores i))
              (incf num (aref ps i))))
          (if (>= score required-score)
              (setf min-num (min num min-num))
              (let ((idx -1)
                    (delta most-positive-fixnum))
                (dotimes (i d)
                  (when (zerop (ldb (byte 1 i) bits))
                    (let ((tmp-delta (ceiling (- required-score score) (+ i 1))))
                      (when (and (< tmp-delta (aref ps i))
                                 (< tmp-delta delta))
                        (setf idx i
                              delta tmp-delta)))))
                (incf num delta)
                (when (and (/= idx -1)
                           (< num min-num))
                  (setf min-num num))))))
      (println min-num))))

#-swank(main)