Bin Packing

You must pack $n$ one-dimensional items into identical bins. Every bin has the same length $l$, and each item $i$ has length $l_i \le l$.

Find the minimum number of bins $q$ such that all of the following hold:

• Each bin contains at most 2 items.
• Every item is packed into exactly one bin.
• The total length of the items in any single bin does not exceed $l$.

Given the integers $n$, $l$, and $l_1, \dots, l_n$, compute the minimum number of bins $q$.

The first line contains the number of items $n$ ($1 \le n \le 10^5$).

The second line contains the bin length $l$ ($1 \le l \le 10000$).

Each of the next $n$ lines contains one item length $l_i$ ($1 \le l_i \le l$).

Print a single line containing the minimum number of bins needed to pack all items.

The figure below shows one optimal packing.