Problems
Divisible Sum Pairs
Divisible Sum Pairs
You are given an array of integers A = (a_0, a_1, ..., a_{n-1}) and a positive integer k. Find and print the number of pairs (i, j) where i < j and a_i + a_j is divisible by k.
Input data
The first line contains integer n~(2 \le n, k \le 100) and k. The second line contains n integers describing the values of A = (a_0, a_1, ..., a_{n-1})~(1 \le a_i \le 100).
Output data
Print the number of pairs (i, j) where i < j and a_i + a_j is divisible by k.
Examples
Input example #1
6 3 1 3 2 6 1 2
Output example #1
5