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;
using System.Text;
using System.Threading.Tasks;

namespace ABC104.Task3
{
    class Program
    {
        static void Main(string[] args)
        {
            var line1 = Console.ReadLine().Split(' ');
            long d = Int64.Parse(line1[0]);
            long g = Int64.Parse(line1[1]);

            var ps = new List<long>();
            var cs = new List<long>();

            long count = 0;

            for (var i = 0; i < d; i++)
            {
                var s = Console.ReadLine().Split(' ');
                var p = Int64.Parse(s[0]);
                ps.Add(p);
                cs.Add(Int64.Parse(s[1]));
                count += p;
            }

            var result = Solve(d, g, count, ps, cs);
            Console.WriteLine(result);
        }

        static long Solve(long d, long g, long count, List<long> ps, List<long> cs)
        {
            long minCount = count;
            var table = new long[d + 1, count + 1];

            for (var j = 0; j <= count; j++)
            {
                table[0, j] = 0;
            }

            for (var i = 1; i <= d; i++)
            {
                for (var j = 0; j <= count; j++)
                {
                    if (j <= ps[i - 1])
                    {
                        table[i, j] = Math.Max(table[i - 1, j], Score(j, i, ps, cs));
                    }
                    else
                    {
                        table[i, j] = Math.Max(table[i - 1, j], table[i - 1, j - ps[i - 1]] + Score(j, i, ps, cs));
                    }
                    // Trace(i, j, table[i, j]);
                    if (table[i, j] >= g)
                    {
                        minCount = Math.Min(minCount, j);
                    }
                }
            }
            return minCount;
        }

        static long Score(int i, int row, List<long> ps, List<long> cs)
        {
            var maxNum = ps[row - 1];
            if (i >= maxNum)
            {
                return maxNum * row * 100 + cs[row - 1];
            }
            else
            {
                return i * row * 100;
            }
        }

        static void Trace(long i, long j, long v)
        {
            Console.WriteLine("({0},{1}) = {2}", i, j, v);
        }
    }
}