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 Go (1.6) (judge verdict: Wrong Answer)

package main

import "fmt"

const inf = 100000

var (
	d, g int
	p, c []int
	cpt  []bool
)

func min(x, y int) int {
	if x < y {
		return x
	}
	return y
}

func dfs(i int) int {
	if i < len(cpt) {
		cpt[i] = true
		x := dfs(i + 1)
		cpt[i] = false
		y := dfs(i + 1)
		return min(x, y)
	}

	cnt, total := 0, 0
	for i := 0; i < d; i++ {
		if cpt[i] {
			total += (i+1)*100*p[i] + c[i]
			cnt += p[i]
		}
	}
	if total >= g {
		return cnt
	}

	maxB, maxP := 0, 0
	for i := 0; i < d; i++ {
		if !cpt[i] {
			if b := (i + 1) * 100; b > maxB {
				maxB = b
				maxP = p[i]
			}
		}
	}
	if maxB == 0 {
		return inf
	}
	n := (g - total) / maxB
	if n >= maxP {
		return inf
	}
	return cnt + n
}

func main() {
	fmt.Scan(&d, &g)

	p = make([]int, d)
	c = make([]int, d)
	for i := 0; i < d; i++ {
		fmt.Scan(&p[i], &c[i])
	}

	cpt = make([]bool, d)
	fmt.Println(dfs(0))
}