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**Task** | Statistics

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

There are $n$ people who want to get to the top of a building which has only one elevator. You know the weight of each person and the maximum allowed weight in the elevator. What is the minimum number of elevator rides?

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.

Print one integer: the minimum number of rides.

- $1 \le n \le 20$

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

- $1 \le w_i \le x$

Input:

`4 10`

4 8 6 1

Output:

`2`