Contest Duration: - (local time) (300 minutes)
A - Credits /

Time Limit: 1 sec / Memory Limit: 256 MB

### 問題文

i 番目の講義に割り当てられている単位数は a_i です。 あなたは最小限の履修で進級したいと考えています。 いくつの授業を履修する必要があるか求めてください。

### 制約

• 1 \leq N \leq 50
• 1 \leq K \leq 1,000
• 1 \leq a_i \leq 20
• N, K, a_i は整数である。

### 入力

N K
a_1 a_2 ... a_N


### 入力例1

5 15
3 8 2 5 6


### 出力例1

3


### 入力例2

5 25
3 8 2 5 6


### 出力例2

-1


### 入力例3

4 20
1 1 20 19


### 出力例3

1


Score : 100 points

### Problem Statement

Kyoto University offers N lectures and you need more than or equal to K credits to advance to the next grade. You can earn a_i credits by taking i-th lecture. You want to take as small number of lectures as possible to advance to the next grade. How many lectures do you need to take?

### Constraints

• 1 \leq N \leq 50
• 1 \leq K \leq 1,000
• 1 \leq a_i \leq 20
• N, K, a_i are integers.

### Input

Input is given from Standard Input in the following format:

N K
a_1 a_2 ... a_N


### Output

Print the minimum number of lectures to advance to the next grade. If you can not advance to the next grade even by taking all the lectures, print -1 instead.

### Sample Input 1

5 15
3 8 2 5 6


### Sample Output 1

3


For example, you can adcance to the next grade with first, second, and fourth lectures.

### Sample Input 2

5 25
3 8 2 5 6


### Sample Output 2

-1


You can not advance to the next grade even by taking all the lectures.

### Sample Input 3

4 20
1 1 20 19


### Sample Output 3

1


KUPC2017