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.Collections.Generic;
using System.Linq;

namespace C
{
    class Program
    {
        static int[] DG = new int[2];
        static void Main(string[] args)
        {
            DG = Console.ReadLine().Split().Select(i => int.Parse(i)).ToArray();
            int index = 0;
            List<Score> pc = Enumerable
                                            .Range(0, DG[0])
                                            .Select(k =>
                                            {
                                                int[] tmp = Console.ReadLine().Split().Select(j => int.Parse(j)).ToArray();
                                                index++;
                                                return new Score {
                                                    num = tmp[0],
                                                    each = index * 100,
                                                    total = tmp[0] * index * 100 + tmp[1]
                                                };
                                            })
                                            .ToList();
            // 1つを途中まで
            // いくつかを完璧に
            // いくつか完璧に、あと一つは途中まで
            int ans = int.MaxValue;
            for (var i = 0; i < (1 << DG[0]); i++)
            {
                int num = 0;
                int score = 0;
                int restMax = -1;
                for (var j = 0; j < DG[0]; j++)
                {
                    if ((i >> j & 1) == 1)
                    {
                        score += pc[j].total;
                        num += pc[j].num;
                    }
                    else
                    {
                        restMax = j;
                    }
                }
                if (score < DG[1])
                {
                    int remain = DG[1] - score + pc[restMax].each - 1;
                    int restNum = remain / pc[restMax].each;
                    if (restNum > pc[restMax].num)
                    {
                        continue;
                    }
                    num += restNum;
                }
                ans = Math.Min(ans, num);
            }
            Console.WriteLine(ans);
        }
    }

    class Score
    {
        public int num;
        public int each;
        public int total;
    }

}