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: Wrong Answer)

#include<bits/stdc++.h>
#define all(v) v.begin(), v.end() 
using namespace std;
typedef long long ll;

const int N = 15;

int d, g;
int p[N], c[N];
int res;

int main() {
   ios_base::sync_with_stdio(false);
   cin.tie(NULL);
   res = 1e9;
   cin >> d >> g;
   for(int i=0; i<d; ++i) {
       cin >> p[i] >> c[i];
   }
   for(int b=0; b<(1<<d); ++b) {
       int tot = 0;
       vector<int> lst;
       for(int i=0; i<d; ++i) {
           if(b & (1<<i)) {
               tot += p[i]*100*(i+1) + c[i];
               lst.push_back(i);
           }
       }
       if(tot < g) continue;
       vector<int> id(lst.size());
       iota(all(id), 0);
       do {
           tot = 0;
           int pr = 0;
           for(int x: id) {
               if(tot >= g) break;
               if(tot + p[lst[x]]*100*(lst[x]+1) <= g) 
                   tot += p[lst[x]] * 100 * (lst[x]+1) + c[lst[x]], pr += p[lst[x]];
               else if(tot < g) {
                   pr += (g-tot)/((100)*(lst[x]+1));
                   break;
               }
           }
           res = min(res, pr);
       } while(next_permutation(all(id)));
   }
   cout << res << "\n";
   return 0;
}