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: Wrong Answer)

import java.util.Scanner;

public class Main {

    public static void main(String[] args){

       // Scanner cin = new Scanner(new FileReader("src\\AtcoderContest0805\\task2-test-input.txt"));
        Scanner cin = new Scanner(System.in);
        int totalNum = cin.nextInt();
        int targetSum = cin.nextInt();
        int[] quesNum = new int[totalNum];
        int[] bonues = new int[totalNum];

        for (int i=0;i<totalNum;i++){
            quesNum[i] = cin.nextInt();
            bonues[i] = cin.nextInt();
        }

        int[] fullAnswerScore = new int[totalNum];

        for (int i=0;i<totalNum;i++) {
            fullAnswerScore[i] = (i+1)*100*quesNum[i]+bonues[i];
        }
        int[] used = new int[totalNum];
        int res = 0;
        while (targetSum>0) {

            int[] everyQuesScore = new int[totalNum];
            int mark = 0;
            for (int i=0;i<totalNum;i++){
                if (fullAnswerScore[i]<targetSum&&used[i]==0) {everyQuesScore[i] = fullAnswerScore[i]/quesNum[i];mark=1;}
                else if (used[i]==1) everyQuesScore[i] = 0;
                else everyQuesScore[i] = (i+1)*100;
            }
            int notSuffCount = Integer.MAX_VALUE;
            if (mark==0) {
               // System.out.println("here");
                for (int i=0;i<totalNum;i++) {
                    if (used[i]==0){
                    int tempNum = 0;
                    while (true) {
                        if (tempNum * (i + 1) * 100 >= targetSum || tempNum >= quesNum[i]) {
                            break;
                        } else tempNum++;
                    }
                   // System.out.println("tempNum " + tempNum);
                    if (tempNum < notSuffCount) notSuffCount = tempNum;
                    if (quesNum[i] < notSuffCount) notSuffCount = quesNum[i];
                    //System.out.println(notSuffCount);
                }
                }
                res+=notSuffCount;
               // System.out.println("res1 "+res);
                break;
            }
            //System.out.println(Arrays.toString(everyQuesScore));
            int max = 0;
            int pos = 0;
            for (int i=0;i<totalNum;i++) {
                if (everyQuesScore[i]>max) {
                    max = everyQuesScore[i];
                    pos = i;
                }
            }
            used[pos] = 1;
            //System.out.println("pos "+pos);
            if (fullAnswerScore[pos]>targetSum){
                int tempNum = 1;
                while (true) {
                    if (tempNum*(pos+1)*100>=targetSum) {
                        res+=tempNum;
                        targetSum = 0;
                        break;
                    }
                    else tempNum++;
                }
            }
            else {
                targetSum-=fullAnswerScore[pos];
                res+=quesNum[pos];
            }
            //System.out.println("remained "+targetSum);

        }
        System.out.println(res);

    }

}