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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>

using namespace std;

const int MAXN=13;
const int MAXS=1000111;
const int INF=1034567890;

int N;
int P[MAXN];
int C[MAXN];
int G;
int Sum;
int MinP[MAXS];

int main(){
	ios_base::sync_with_stdio(false);
	
	cin >> N >> G;G/=100;
	for(int i=1;i<=N;++i){
		cin >> P[i] >> C[i];
		C[i]/=100;
	}
	
	for(int i=1;i<=N;++i){
		Sum+=C[i];
		Sum+=P[i]*i;
	}
	
	MinP[0]=0;
	for(int i=1;i<=Sum;++i)	MinP[i]=INF;
	
	for(int i=1, v;i<=N;++i){
		for(int k=Sum;k>=0;--k){
			for(int j=0;j<P[i];++j){
				v=j*i;
				if(k>=v)	MinP[k]=min(MinP[k], MinP[k-v]+j);
			}
			v=P[i]*i+C[i];
			if(k>=v)	MinP[k]=min(MinP[k], MinP[k-v]+P[i]);
		}
	}
	
	int Ans=INF;
	for(int i=G;i<=Sum;++i){
		if(Ans>MinP[i]){
			Ans=MinP[i];
		}
	}
	
	
	cout << Ans << endl;
	
	return 0;
}