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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;

public class Main {

	public static void main(String[] args) throws NumberFormatException, IOException {

		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		String[] dg = br.readLine().split(" ");
		int d = Integer.parseInt(dg[0]);
		int g = Integer.parseInt(dg[1]);

		HashMap<Integer, String[]> map = new HashMap<Integer, String[]>();
		for (int i = 0; i < d; i++) {
			map.put(new Integer((i + 1) * 100), br.readLine().split(" "));
		}

		AtomicInteger min = new AtomicInteger(99999);

		defs(map, g, 0, min);

		System.out.println(min.get());

	}

	public static void defs(HashMap<Integer, String[]> map, int g, int count, AtomicInteger min) {
		Set<Integer> set = map.keySet();
		for (Integer point : set) {
			int gc = g;
			int countc = count;
			String[] pointinfo = map.get(point);
			int monsuu = Integer.parseInt(pointinfo[0]);
			int bonus = Integer.parseInt(pointinfo[1]);
			if (monsuu * point + bonus < gc) {
				gc -= monsuu * point + bonus;
				countc += monsuu;
			} else {
				for (int i = 0; i < monsuu; i++) {
					gc -= point;
					countc++;
					if (min.get() <= countc) {
						continue;
					}
					if (gc <= 0) {
						if (countc < min.get()) {
							min.set(countc);
						}
						continue;
					}
				}
				gc -= bonus;
				if (gc <= 0) {
					if (countc < min.get()) {
						min.set(countc);
					}
					continue;
				}
			}
			HashMap<Integer, String[]> newmap = new HashMap<Integer, String[]>(map);
			newmap.remove(point);
			defs(newmap, gc, countc, min);
		}
	}

}