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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;
using System.Text;

public class Program
{

    public void Proc()
    {
        int[] inpt = Reader.ReadLine().Split(' ').Select(a => int.Parse(a)).ToArray();

        int itemCount = inpt[0];

        this.Target = inpt[1];

        for (int i = 1; i <= itemCount; i++) {
            inpt = Reader.ReadLine().Split(' ').Select(a => int.Parse(a)).ToArray();
            this.Haiten.Add(i * 100, inpt[0]);
            this.Complete.Add(i * 100, inpt[1]);
        }
        this.KeyList = this.Haiten.Keys.OrderByDescending(a => a).ToArray();

        int ans = GetAns(0, this.Target);
        Console.WriteLine(ans);
    }

    private int Target;

    private Dictionary<int, int> Complete = new Dictionary<int, int>();
    private Dictionary<int, int> Haiten = new Dictionary<int, int>();


    private int GetAns(int idx, int remain) {
        if(remain <= 0) {
            return 0;
        }
        if(idx >= this.KeyList.Length) {
            return -1;
        }
        if(!dic.ContainsKey(idx)) {
            dic.Add(idx, new Dictionary<int, int>());
        }
        if(dic[idx].ContainsKey(remain)) {
            return dic[idx][remain];
        }

        int ans = int.MaxValue;
        int unit = KeyList[idx];

        for (int i = 0; i < Haiten[unit]; i++) {
            int tmp = GetAns(idx + 1, remain - (unit * i));
            if(tmp < 0) {
                continue;
            }
            tmp += i;
            ans = Math.Min(ans, tmp);
        }
        int t2 = GetAns(idx + 1, remain - (unit * Haiten[unit] + Complete[unit]));
        if(t2 >= 0) {
            t2 += Haiten[unit];
            ans = Math.Min(ans, t2);
        }
        if(ans == int.MaxValue) {
            ans = -1;
        }
        dic[idx][remain] = ans;
        return ans;
    }

    private int[] KeyList;
    private Dictionary<int, Dictionary<int, int>> dic = new Dictionary<int, Dictionary<int, int>>();

    public class Reader
    {
        static StringReader sr;
        public static bool IsDebug = false;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (sr == null)
                {
                    sr = new StringReader(InputText.Trim());
                }
                return sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }
        private static string InputText = @"




5 25000
20 1000
40 1000
50 1000
30 1000
1 1000


";
    }

    public static void Main(string[] args)
    {
#if DEBUG
        Reader.IsDebug = true;
#endif
        Program prg = new Program();
        prg.Proc();
    }
}