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)

(defvar +inf+ most-positive-fixnum)

(defun most-difficult-problem-index (d bits)
  (loop for i from (1- d) downto 0
        if (not (logbitp i bits))
        do (return i)))

(defun bits-problem-counts (d bits problems)
  (loop for i from 0 to d
        if (logbitp i bits)
        sum (car (nth i problems))))

(defun solve (d g problems)
  (loop for bits from 0 below (expt 2 d)
        for points = (loop for i from 0 below d
                           if (logbitp i bits)
                           sum (destructuring-bind (count . bonus)
                                   (nth i problems)
                                 (+ bonus (* count (1+ i) 100))))
        minimize
        (cond
          ((<= g points)
           (bits-problem-counts d bits problems))
          ((most-difficult-problem-index d bits)
           (let ((j (most-difficult-problem-index d bits)))
             (let ((extra-counts (ceiling (- g points)
                                          (* 100 (1+ j)))))
               (if (<= extra-counts (car (nth j problems)))
                   (+ (bits-problem-counts d bits problems)
                      extra-counts)
                   +inf+))))
          (t +inf+))))

#-swank
(let* ((d (read))
       (g (read))
       (problems (loop repeat d
                       collect (cons (read) (read)))))
  (format t "~A~%" (solve d g problems)))