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# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ProblemF
{
    class Program
    {
        // Beg 104 C
        static void Main(string[] args)
        {
            var read = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            var D = read[0];
            var G = read[1] / 100;

            var ps = new int[D];
            var cs = new int[D];
            var compScores = new int[D];

            for (int i = 0; i < D; i++)
            {
                read = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
                ps[i] = read[0];
                cs[i] = read[1] / 100;
                compScores[i] = (i + 1) * ps[i] + cs[i];
            }

            var iter = Math.Pow(2, D);
            var res = 1000;
            for (int i = 0; i < iter; i++)
            {
                var tempSum = 0;
                var tempProbNum = 0;
                for (int j = 0; j < D; j++)
                {
                    if((i & 1<<(D - j - 1)) != 0)
                    {
                        tempSum += compScores[j];
                        tempProbNum += ps[j];
                    }
                }
                if (G <= tempSum)
                    res = Math.Min(tempProbNum, res);
                else
                {
                    var notUsedNums = Enumerable.Range(0, D - 1).Where(k => (i & 1 << (D - k - 1)) == 0);
                    if (notUsedNums.Count() == 0)
                        continue;
                    var maxProbNum = notUsedNums.Max() + 1;
                    if(G <= tempSum + maxProbNum * ps[maxProbNum - 1])
                    {
                        var num = (G - tempSum) % maxProbNum == 0 ? (G - tempSum) / maxProbNum : (G - tempSum) / maxProbNum + 1;
                        res = Math.Min(tempProbNum + Math.Min(num, ps[maxProbNum - 1]), res);
                    }
                }
            }
            Console.WriteLine(res);

            //var tempG = G;
            //var resProbNum = 0;
            //for (int i = D; i > 0; i--)
            //{
            //    if(tempG - (compScores[i - 1]) <= 0)
            //    {
            //        var num = tempG % i == 0 ? tempG / i : tempG / i + 1;
            //        resProbNum += Math.Min(num, ps[i - 1]);
            //    }
            //    else
            //    {
            //        resProbNum += ps[i - 1];
            //        tempG -= compScores[i - 1];
            //    }
            //}
        }
    }
}