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: Time Limit Exceeded)

#3
d,g = map(int,input().split())
lista = []
for i in range(d):
    lista.append([])
    p,c = map(int,input().split())
    lista[i] = [p,c]
    
def search(allcomp,notouch,touch,rem,toachiev,ps):
    #allcomp 全部解く
    #notouch 触らない
    #touch 触る
    #残りの選択肢
    #達成までに必要な得点
    #ここまで解いてる問題数
    if touch != []:
        #print(allcomp,notouch,touch,rem,toachiev,ps)
        point = (touch[0] + 1)*100
        problems = lista[touch[0]][0]
        vnus =  lista[touch[0]][1]
        #print(point,problems,vnus)
        if toachiev == 0:
            return ps
        else:
            needproblems = toachiev//point
            if toachiev%point != 0:
                needproblems += 1
                
            if needproblems<=problems:
                return ps+needproblems
            else:
                if point*problems + vnus >= toachiev:
                    return ps+problems
                else:
                    return 10**9
                
    else:
        if len(rem)==1:
            rempoint = (rem[0] + 1)*100
            notouchpoint_max = 0
            if notouch != []:
                notouchpoint_max = (max(notouch) + 1)*100
            
            if notouchpoint_max <= rempoint:
                return search(allcomp,notouch,rem,[],toachiev,ps)
            else:
                return 10**9
        else:
            minp = 10**9
            for i in range(len(rem)):
                allcomp_t,notouch_t,rem_t,toachiev_t,ps_t = list(allcomp),list(notouch),list(rem),toachiev,ps
                allcomp_t.append(rem[i])
                rem_t = rem[:i]+rem[i+1:]
                toachiev_t = toachiev_t - (rem[i] + 1)*100*lista[rem[i]][0] - lista[rem[i]][1]
                if toachiev_t <0:
                    toachiev_t = 0
                ps_t = ps_t + lista[rem[i]][0]
                case1 = search(allcomp_t,notouch_t,[],rem_t,toachiev_t,ps_t)
                
                allcomp_t,notouch_t,rem_t,toachiev_t,ps_t = list(allcomp),list(notouch),list(rem),toachiev,ps
                notouch_t.append(rem[i])
                rem_t = rem[:i]+rem[i+1:]
                case2 = search(allcomp_t,notouch_t,[],rem_t,toachiev_t,ps_t)
                #print(case1,case2)
                if minp > min(case1,case2):
                    minp = min(case1,case2)
                    
            return minp
                
        
        
        
        
makerem = []
for i in range(d):
    makerem.append(i)
    
print(search([],[],[],makerem,g,0))