**Time limit:**1.00 s**Memory limit:**512 MB

**Input**

The first input line has two integers $n$ and $x$: the number of people and the maximum allowed weight in the elevator.

The second line has $n$ integers $w_1,w_2,\dots,w_n$: the weight of each person.

**Output**

Print one integer: the minimum number of rides.

**Constraints**

- $1 \le n \le 20$

- $1 \le x \le 10^9$

- $1 \le w_i \le x$

**Example**

Input:

`4 10`

4 8 6 1

Output:

`2`