A12388 | Preparation for International Women's Day

International Women's Day is coming soon! Polycarp is preparing for the holiday.

There are $n$ candy boxes in the shop for sale. The $i$ -th box contains $d_i$ candies.

Polycarp wants to prepare the maximum number of gifts for $k$ girls. Each gift will consist of exactly two boxes. The girls should be able to share each gift equally, so the total amount of candies in a gift (in a pair of boxes) should be divisible by $k$ . In other words, two boxes $i$ and $j$ ( $i \ne j$ ) can be combined as a gift if $d_i + d_j$ is divisible by $k$ .

How many boxes will Polycarp be able to give? Of course, each box can be a part of no more than one gift. Polycarp cannot use boxes "partially" or redistribute candies between them.

The first line of the input contains two integers $n$ and $k$ ( $1 \le n \le 2 \cdot 10^5, 1 \le k \le 100$ ) — the number the boxes and the number the girls.

The second line of the input contains $n$ integers $d_1, d_2, \dots, d_n$ ( $1 \le d_i \le 10^9$ ), where $d_i$ is the number of candies in the $i$ -th box.

Print one integer — the maximum number of the boxes Polycarp can give as gifts.