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 Kotlin (1.0.0) (judge verdict: Accepted)

data class PC(val p: Int, val c: Int) {
    constructor(pc: List<Int>): this(pc[0], pc[1])
}
fun main(args: Array<String>) {
    var (D, G) = listOfInt()
    val pc = Array(D) { PC(listOfInt()) }
    var ans = Int.MAX_VALUE
    var mask = 0
    while(mask < 1.shl(D)) {
        try {
            var s = 0
            var num = 0
            var rest_max = -1
            for (d in 0 until D) {
                if (mask.ushr(d) and 1 != 0) {
                    s += 100 * (d + 1) * pc[d].p + pc[d].c
                    num += pc[d].p
                } else rest_max = d
            }
            if (s < G) {
                val s1 = 100 * (rest_max + 1)
                val need = (G - s + (s1 - 1)) / s1
                if (need >= pc[rest_max].p) continue
                num += need
            }
            ans = Math.min(ans, num)
        } finally {
            mask += 1
        }
    }
    println(ans)
}

fun next() = readLine()!!
fun nextInt() = Integer.parseInt(next())
fun nextInt(offset: Int = 0) = nextInt() + offset
fun listOfString() = next().split(" ")
fun listOfInt() = listOfString().map { Integer.parseInt(it) }