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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

import qualified Data.Map as M

f ::Int->Int->Int->Int->[(Int,Int)]
f n n2 b add
   |n<=n2=[(n2,n2*b+add)]
   |otherwise=(n2,n2*b):f n (n2+1) b add

f2 ::String->(Int,Int)
f2 x=let (a:b:[])=(map read . words) x::[Int]
     in (a,b `div` 100)

f3::[(Int,Int)]->[(Int,Int)]->[(Int,Int)]->[(Int,Int)]
f3 _ _ []=[]
f3 [] xs2 (y:ys)=f3 xs2 xs2 ys
f3 ((c1,p1):xs1) xs2 ((c2,p2):ys)=((c1+c2),(p1+p2)):(f3 xs1 xs2 ((c2,p2):ys))

f5::Int->Int->Int
f5 a b
 |a>b=a
 |otherwise=b

f4::Int->[(Int,Int)]->[(Int,Int)]->[(Int,Int)]
f4 _ [] ys=ys
f4 b1 ((c1,p1):xs) ys=let zs= (f c1 0 b1 p1)
                      in f4 (b1+1) xs (M.toList (M.fromListWith (f5) (f3 zs zs ys)))
f6 :: Int->[(Int,Int)]->Int
f6 _ []=1
f6 n ((c,p):xs)
    |n<=p=c
    |otherwise=f6 n xs

main = do
       a<-getLine
       b<-getContents
       let xs=lines b
           (n:m:[])=(map read . words) a::[Int]
           m2=m `div` 100
           ys=(map f2) xs
       --print $ f3 (f 3 0 1 5) (f 3 0 1 5) [(0,0)]
       print $ f6 m2 $ f4 1 ys [(0,0)]