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: Wrong Answer)

import Control.Monad
import qualified Data.ByteString.Char8 as BC
import Data.Maybe (fromJust)
import Data.List

readIntsLines :: IO [[Int]]
readIntsLines = map (map (fst . fromJust . BC.readInt) . BC.words) . BC.lines <$> BC.getContents

solve :: Int -> [[(Bool, Int, Int, Int)]] -> [Int]
solve _ [] = []
solve g (pt:pts) = count g pt:solve g pts

count :: Int -> [(Bool, Int, Int, Int)] -> Int
count g pt = if g <= result
             then num
             else if result2 /= 0 then result2 else 10 ^ 7
  where result = sum $ map calc pt
        result2 = num + rest (g - result) pt
        num = sum $ map countNum pt
        calc (enable, point, count, bonus) = if enable then point * count + bonus else 0
        countNum (enable, _, count, _) = if enable then count else 0
        

rest :: Int ->  [(Bool, Int, Int, Int)] -> Int
rest g pt = target
  where enable (b, _, _, _) = not b
        compPoint (_, p1, _, _) (_, p2, _, _) = compare p1 p2
        filtered = sortBy compPoint $ filter enable pt
        target = if null filtered
                 then 0
                 else let (_, point, count, _) = last filtered in
                      if g `div` point >= count
                      then 10 ^ 7
                      else g `div` point

to2ple [x, y] = (x, y)
to4ple ((a, b), (c, d)) = (d, c, a, b)

main :: IO ()
main = do
  [d, g] <- map read . words <$> getLine
  pcs <- map to2ple <$> readIntsLines
  let ds = zip [100,200..] <$> replicateM d [True, False]
  print . minimum . solve g $ map (map to4ple) $ zip pcs <$> ds