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 (3.4.3) (judge verdict: Accepted)

D,G = map(int,input().split()) #Gは達成すべきスコア。Dは100D点問題まであるって事を示す。
L = []
minimum = 0 #解くべき最低問題数
candidate = 0 #あるループで解いた問題数
score = 0
for _ in range(D):
    p,c = map(int,input().split())
    L.append([p,c]) #k個目の問題はpk個あって、全部正解するとc点もらえる。
#2 700
#3 500
#5 800の場合：[[3, 500], [5, 800]]を得る。
#方針：全部ACの線で問題探して行って、それでダメならgreedyに全完してないやつから難易度順にACして行く。
#まず全完難易度帯を2^D通り決め打ちする。
for i in range(2**D):
    for j in range(len(L)): #list L に対応したフラグ立ってるか見る。
        if ((i>>j)& 1): #立っていれば：
            score += L[j][0] * (j+1) * 100 + L[j][1] #全完した
            candidate += L[j][0]
    if score >= G:#目標達成
        if minimum == 0:
            minimum = candidate #minimum初期化
            candidate = 0 #candidateリセット
            score = 0
        elif candidate != 0 and candidate < minimum:
            minimum = candidate #minimum更新
            candidate = 0 #リセット
            score = 0
    else: #失敗
        for j in range(len(L)-1,-1,-1):
            if ((i>>j) & 1):#立っていれば：
                continue #次の処理はしないでください。
            for k in range(L[j][0]):#全完されてない難易度を見つけた。L[j][0] = k問でリサーチ。
                score += 100*(j+1) #j問目正解
                candidate += 1
                if score >= G:
                    if minimum == 0:
                        minimum = candidate #minimum初期化
                        candidate = 0 #candidateリセット
                        score = 0
                    elif candidate != 0 and candidate < minimum:
                        minimum = candidate #minimum更新
                        candidate = 0 #リセット
                        score = 0
    candidate = 0 #リセット
    score = 0
print(minimum)