Nums That Are Divisible by N

Count the index pairs with i<j such that a[i]+a[j] is divisible by N. Elements with duplicate values still have distinct identities, and an element cannot be paired with itself.

输入格式

The first line contains the array length n and the divisor N, and the second line contains n numbers. Complete original bounds: 1≤n≤100000, 1≤N≤10^9, 1≤a[i]≤10^9; output a 64-bit integer.

输出格式

Output one integer answer.

样例 1

输入：

5 3
5 4 3 2 1

输出：

4

样例 2

输入：

3 2
1 1 1

输出：

3

样例 3

输入：

1 3
3

输出：

0

样例说明

The first example has 4 pairs: original indices (0,1), (0,4), (1,3), and (3,4). The original explanation reversed the array without updating the indices accordingly; this site corrects it. The other two examples give 3 and 0.