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 Fortran (gfortran v4.8.4) (judge verdict: Accepted)

program main
implicit None
integer(8)::d,g,i,s,n,j,k,ma
integer(8),allocatable::p(:),c(:),a(:),e(:)
character::b*10,f*1
	
	read*,d,g
	g = g/100
	allocate(p(d),c(d),a(d),e(d))
	do i = 1,d
		read *,p(i),c(i)
		c(i) = c(i)/100
		a(i) = i*p(i)+c(i)
	enddo
	
	k = sum(p)
	
	do i = 0,2**d-1
		write(b,"(b10.10)")i
		e =0
		do j = 11-d,10
			f = b(j:j)
			read(f,"(i1)")e(11-j)
		enddo
		s =0;n =0
		do j = 1,d
			s = s + a(j)*e(j)
			n = n + p(j)*e(j)
		enddo
		
		if(s >=g)then
			if(n < k) k = n
			cycle
		endif
		
		do j = d,1,-1
			if(e(j) == 0) exit
		enddo
		
		if(g-s <= j*p(j))then
			n = n + (g-s)/j
			if(mod(g-s,j)/=0) n = n+1
			if(n < k) k = n
		endif
	enddo
	
	print "(i0)",k
	
end program main