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 Python (3.8.2) (judge verdict: Accepted)

P=[]
C=[]
point=1001    #全問題数
 
D,G=map(int,input().split())
for i in range(D):
    p,c= map(int,input().split())
    P.append(p)
    C.append(c)
 
#とりあえず全部解くor解かないで目標スコアを超えるか超えないかを考える
 
 
for i in range(2**D) :
    score=0
    solve=0
    needproblem=0
    for j in range(D) :                  #全正解した大問をスコアに変換
        if (i>>j) & 1 :
            score+=P[j]*100*(j+1)+C[j]
            solve+=P[j]
        if (~i>>j) & 1 :                  #1問も解かなかった問題の中で最も一題あたりの点が高い問題
            needproblem=j+1
    if score>=G :
        point=min(point,solve)
 
#ぎりぎりスコアが届いていない場合、1問も解かなかった問題の中で最も一題あたりの点が高い問題だけ解いてみる
#中途半端に大問を解ききるのが１種類以下でも目標に届く場合もあるという予想
 
    elif score<G :                
        rest=G-score
        sum=(P[needproblem-1]-1)*needproblem*100
        if rest>sum :            #1問も解かなかった問題の中で最も一題あたりの点が高い問題を解いても届かないのでやり直し
            continue
        elif rest<=sum :
            resolve=solve+(rest//(needproblem*100)+(rest%(needproblem*100)>0))
            point=min(point,resolve)
 
print(point)